re: Anyone had mono as an adult?

Yes. Pretty much the same story as in your first paragraph. Came down with virus like symptoms, fever, chills, body aches, etc.

Doctor would give me the rural family med special....a steroid shot and a z pack. Would feel great for a few days, and then start running fever again. Rinse and repeat. 4th visit within a few weeks I was running another fever. He tested me for mono. I was positive and septic at that point. Fever spiked to 105 in the doctors office. Admitted into hospital immediately, given an ice bath to get my temp down. stayed on an IV antiobiotic drip for over a week. I don't remember what it was, but the doctor said it would kill anything short of cancer and aids.

Went from 185 to 130 pounds in the weeks prior to being diagnosed, had to get tonsils and adenoids removed, the whole nine yards.

I was 21 and in college at the time. Not a fun experience. Took almost 2 years to fully recover.

10/10 do not recommend.