Re: Hashimoto's Flare Up???
Yes, tigger, this can happen. It could be your Hashi's flaring, or it could be a viral or other sort of thyroiditis on top of your Hashi's.
Why not calll your endo's office & explain what's going on? Most docs schedule "check-ups" a ways out, but also have openings for urgent concerns. Endos esp., as they deal a lot with diabetics who can have some crisis mode occurrences.
If your endo can't see you within a few days, or says "go to your PCP," then that's your Plan B.