Fever like symptoms with no present fever?

For some reason the past few months i’ve been having random days where i’m convinced i have a high fever and feel rotten but check my temperature and it’s normal. It’s been really cold recently reaching freezing temperatures and my body’s not handling it well. Like you know when u have a flu and u just can’t physically warm up except from showering or being burried in piles of blankets, that kind of feeling. Is this normal with POTS? or is it something else i should look into.