If your endo started thyroid replacement two months ago, you will have a blood level checked at the follow-up appt. If your thyroid has just started to poop-out, you may need the med. dose increased. Sometimes it takes a while to get thyroid issues leveled out. Your Vit D level will probably be checked again.

Hang in there - at 28 I doubt you face a lifetime of feeling bad. Fatigue is frequently a tricky thing to diagnose and treat.