Taking the pill separate from food and nutritional supplements can reduce problems with variable absorption of the dose you take. If you always take your thyroid replacement pill with oatmeal, on a full stomach, then as long as you continue to take it that same way, you should do just fine, since the amount of your dose has been adapted to that. If you started taking it on an empty stomach at this point, your body might use it more efficiently, which could make you hyper.
Dianne W