Usually, the recommendation is first thing when we get up with one full glass of water and wait about an hour before eating. Food can interfere with the uptake of hormones. You can also take it at bedtime as long as you've last eaten about 2.5 to 3 hours as stomach has to be empty.
Vitamins/minerals can be taken at lunchtime as most have to be taken with food.
As you have hashimoto's going gluten-free can help reduce the attack on your thyroid gland.
Deficiencies in vitamins/minerals can cause clinical symptoms and B12 in particular pins/needles. Weight gain is the most asked query and sometimes its because we aren't yet on an optimum or dose is kept too low so that our metabolism isn't raised sufficiently. Both Vitamin D and B12 are essential pro-hormones and need to be optimum. B12 for instance should be around 1,000.
You need both Free T4 and Free T3 checked as low T3 can cause depression.
Levothyroxine is T4 only and it has to convert to T3 the only Active thyroid hormone required in our receptor cells, so we need sufficient or a T4/T3 combination. The following is a list of clinical symptoms and, in theory, with optimum dose of thyroid hormones we shouldn't have any.