Levothyroxin is the biological equivalent of T4, so the body uses it naturally. But it is important how you take it. You must be consistent, and take it first thing in the morning with a glass of water, and then wait at least a half hour or more before eating anything. And you should wait to take supplements or vitamins until four hours after the levothyroxin. The issue is that some substances in foods (like iron) and supplements/vitamins can attach themselves to the levothyroxin and keep it from being absorbed into your blood. Or keep some of it from being absorbed. By taking it before eating anything, you assure that you are getting the same amount absorbed every day. This helps you get your levels balanced quicker, and keep them that way.
I hope you feel better soon.
Let us know how you’re doing as the levothyroxine kicks in