So this is what all the hype’s about! I was glowing. I was infatuated. I was walking on air. I was more alive than ever. At 28, I was helplessly, hopelessly falling in love for the very first time. Sure, I had had my fair share of teen and twenty-something crushes up to that point, but those were nothing like this!

With the man of my dreams equally smitten, I was suddenly finding myself in the throes of one of the most exhilarating, significant and emotionally intense experiences of my life. If you’re lucky, you can relate.

Often likened to having a mental illness or drug dependency, romantic love is in many cases unplanned, inconvenient, involuntary and seemingly absurd.

In trying to make sense of the seemingly uncontrollable, the Romans believed that Cupid, the naughty angel, randomly shot his arrow at unsuspecting victims. The little bugger had gotten me all right, unexpectedly impacting my focus in the midst of my pursuit of a doctorate.

Deliciously delirious with love’s intoxicating effects, I realized that this temporary state of insanity was actually invaluable in my sexuality studies. I could finally fully respond to a question often asked by my students and Web site visitors: How do you know when you’re truly falling in love?

It's a question that is probably on the minds of many people with Valentine's Day just days away.

As brilliantly described in Dr. Helen Fisher’s “Why We Love,” here's how you know when you’re love-struck:

You’re suddenly shy, at least initially. Even the most confident can feel timid, anxious, awkward, and even fearful around a crush. You may turn pale, flush, tremble, stammer, sweat, feel dizzy, breathe faster, get weak in the knees and have “butterflies in your stomach.” While such symptoms are flu-like, you’ve been struck with no more than a love bug.

You’re suddenly manic. You may have lost your appetite or find yourself sleepless, yet feeling totally energized, even hyperactive. Know that you have your brain to blame. Elevated concentrations of dopamine, and its chemical derivative norepinephrine, are basically hijacking your brain, lowering your serotonin levels. These neuron-transmitters, known as monoamines, are what make us feel loopy with love.

You’re obsessed. Your “love object” has taken on what psychologists call a “special meaning.” This sweetie has become unique, novel, and all-important — the center of your universe. You are infatuated, focusing your energy and passion on every little thing associated with your honey.

Elevated levels of dopamine in your brain make for more focused attention and motivation in directing and attaining your amour goals. You are consumed with “intrusive thinking,” fantasizing and daydreaming constantly about your beloved. One survey found that the love-obsessed reported thinking of their beloved for more than 85 percent of their waking hours. Not surprisingly, couples can describe how they fell in love with each other years later.

You’ve changed. You may find that you’re revamping yourself. Between your clothing style, mannerisms, habits, and even values, you’re willing to do almost anything and everything to win your loved one’s affections.

You’re on the ride of your life. Until the relationship offers security, you may feel like you’re on a roller coaster. When things are good, you’re on “cloud 9.” But if a loved one is unresponsive right away, indicates something negative, seems indifferent ... basically, does anything to rattle you, you may feel despair, depressed, rage, mopey and listless until the situation is resolved. In Fisher’s survey, 79 percent of men and 83 percent of women reported dissecting an adored one’s actions.

You’re sporting rose-colored glasses these days. Passion makes for perfect. While the love-struck can name faults their love object has, unlike the rest of us, they see these defects as charming and endearing. Love is blind. And you are willing to go to great lengths to make sure that the illusion you’ve created remains unscathed.

You have no desire for anyone else. You want sexual and emotional union with your one and only. Yet while lust — the craving for sexual gratification — is a major player in your passion pursuits — the desire for sex and monogamy are less important than the desire for an emotional union. Men and women ache to have their love returned more than anything.

Believe it or not, it seems that Mother Nature wanted to bestow all of the aforementioned on us during the attraction stage of coupledom. Lust is said to have evolved to motivate humans to seek sexual relations with almost any semi-appropriate partner. Romantic love, however, helps us to focus our mating attention on a specific person, helping us to conserve our energy and time with one courtship. Feelings of attachment, and its components of peace, calm and security, then take over for the long haul. With many arguing that this passionate state of affairs lasts no more than two years, be sure to enjoy this love drug while it lasts!

In the Know, Sex News …

— Government promotes sexual well-being. Britain’s NHS has added “sexercise” as a means to better health. With the NHS Direct Web site citing a lowered risk of heart attack and longer life span as incentives, one has to wonder which other governments will follow suit.

— Unimpressive efforts in Illinois. An article in Obstetrics & Gynecology has found that nearly one in three sex education teachers in Illinois public schools are not trained for such instruction. Furthermore, the state’s school-based sex education focused the most attention on HIV/AIDS, STDs, and abstinence-until-marriage. The least frequently taught topics included emergency contraception, sexual orientation, and condoms and other contraceptives.

— African youth need information. According to the African Journal of Reproductive Health, new survey data on 12- to 14-year-olds in Burkina Faso, Ghana, Malawi, and Uganda found that they are already sexually active. While the youth were aware of pregnancy and HIV, the youth had little in-depth knowledge about either. Researchers are recommending school-based sex education as a promising avenue for equipping young people with the information they need.

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Dr. Yvonne Kristín Fulbright is a sex educator, relationship expert, columnist and founder of Sexuality Source Inc. She is the author of several books including, "Touch Me There! A Hands-On Guide to Your Orgasmic Hot Spots."