If you are running a fever, the last thing you want is to get warmer. Take tylenol or ibuprofren or naproxen and don't bundle up.

My wife is like that, she gets sick and won't take the appropriate meds, then gets the chills and wants to bundle up. She did that one time and her fever went from 101 to 104+ and I ended up stripping her down and throwing her in the tub after getting some advil in her. 15 minutes later her temp came down to managable and the chills reduced and she was able to lay in bed comfortably with just a sheet on.

If you know you are running a fever, don't treat the symptom by bundling up, you will only make matters worse.