I have hashimoto's thyroiditis with 2 nodules on my thyroid and had a sudden drop in vitamin d- what's going on?

No need for panic: Small thyroid nodules is frequently encountered in people with hashimotos. These nodules seem to be small and of no clinical significance unless size is greater than 1 CM and/or worrisome findings per radiologist. Drop in vitamin d is not related but is certainltly of importance and i'm glad you were screened for. Your sun exposure is likely inadequate and depending on levels you may need suppleme.

Parathyroid : It can be difficult to distinguish between a thyroid nodule and a parathyroid adenoma without a specially trained radiologist. Low vitamin d is very common in the general population, but if your level was previously normal and suddenly low, your doctor may need to evaluate you for hyperparathyroidism. Most of the time it causes elevation in blood calcium levels, too.