I appreciate the info. I had assumed that it was probably related to folate or B12 (seemed too likely given everything else). My ferritin has gone from being too high (228) to 52 the last time it was checked. Not certain why. RBC folate was also VERY high at the time of that high ferritin reading. MCV has been pretty consistent since becoming ill again (abnormally high by a little). Does not seem to be changing despite a big change in how I feel overall, so clearly something hasn't been addressed yet. Dealing with any potential thyroid issues has been mostly on hold while I try to pin down some of my more obvious symptoms. Once other things are more stable, I'll be looking there if there are still signs of a problem.