The "Younger" star, 55, took to Instagram early Tuesday to thank her friends, followers and family for an "outpouring of love and support" as she combats the virus at home under quarantine.
Mazar explained that the many well-wishes she received since revealing her diagnosis has "really made me feel good." She then shared her symptoms 10 days into feeling sick.
"I want you to know that I'm doing OK," Mazar said in a video she filmed inside of her home. "I'm on day 10 of really being in the thick of the symptoms. I'm on day 10 of having a low-grade fever. My fever goes up and down anywhere from 102-something to 99-something to 101. It really is a variable."
The actress then shared her initial concern of not making it out alive after contracting the virus.
"My biggest fear was my lungs. I've been a smoker for many, many years and I've had chronic bronchitis since I was a kid," she explained.
"One of my biggest fears was that I wouldn't survive this virus given all the stories I've heard and seen what I've seen."
Mazar said she had a virtual doctor's appointment on Monday and was prescribed an Albuterol inhaler, which she feels "really helped" in addition to taking Tylenol and resting.
"I'm pulling through," Mazar said positively. "You have to take this virus very seriously. In a matter of hours, it can turn on you and you have to pay attention to your symptoms."
Mazar also cleared up confusion over whether or not she was tested and how. She described being tested at an urgent clinic on March 17 after being told by a physician that she did not meet the criteria, meaning she had not recently returned from China or Italy and had not been exposed to somebody first-hand with the illness.
She said she finds the criteria "really unfair" considering, like many others, she likely picked up the virus while running a myriad of daily errands in New York City.
"Meanwhile, I'm a New Yorker. I've been to the theater. I've been to the restaurants, I've been in Ubers, I've gone to the grocery store, Whole Foods, the pharmacy," she listed. "I was one of the millions of people running around trying to buy canned goods and some bleached wipes...in and out of stores on the hunt in New York. We're all touching stuff. No matter how hard you try, you're always going to touch your face."
Mazar, like many others who have spoken out about their symptoms of COVID-19, said the "weirdest" side effect yet is losing her sense of smell and taste.
Additionally, the "Goodfellas" star said she's endured "horrible" headaches daily and has stepped away from technology as a means to heal without added noise.
"I just needed to hear some music, light a candle, feel rested and not consumed with constant information," she added.
The actress also voiced her concerns with the lack of movement happening at the federal level, in terms of getting necessary medical equipment to help physicians combat the virus.
"I don't want to politicize this but the fact that they haven't enacted the defense fund to produce masks, ventilators -- I really don't get it," Mazar said, adding that she has "so much gratitude" for the medical professionals who are "putting themselves in harm's way" to save others.
Mazar pleaded with her followers to "stay home, stay put, stay healthy" as many states around the country have mandated stay-at-home policies in order to prevent the spread.
"Please don't take this virus lightly," she warned. "It's really, really, really strong and it's really, really scary, and it's going to kill a lot of people."
In addition to Mazar, Tom Hanks, Idris Elba and Daniel Dae Kim are among the other celebrities to have tested positive for coronavirus.