Miller revealed the worst of the symptoms in an interview with Kent Babb of the Washington Post:
"Not being able to breathe. I got asthma, but it was past the asthma attack—like my lungs were constricting. My asthma nebulizer helped, but it still didn’t feel like it was supposed to. That was the most frightening part. Just going to sleep knowing that my oxygen level could drop and I could wake up and have to go to the hospital.
"You can’t really taste. You can’t really smell. That in turn kind of messes with your appetite, so you’re not really eating like you’re supposed to. The first four, five days I was honestly nervous. I wouldn’t say that I thought I was going to die or anything like that, but it did cross my mind a little bit."
Miller had previously said he was taking the virus seriously and making precautions but still contracted the disease.
"I wasn't out and about. It hit me right here in my house," he told NFL Live, via ESPN's Jeff Legworld.
Miller now wants to pass what he's learned to his teammates and others around the league.
"They don't even think it's real," he said, per Babb. "That's the craziest part. I told them to take it serious. Take all of this serious. Take social distancing serious."
The coronavirus has led to more than 80,000 deaths in the United States as of Wednesday, per CNN.com.
Miller said he has returned to training after a 17-day absence.