Great question, and I wish I had an easy answer.

Have you had some blood work done? There are tests they can run to check your thyroid, and to see if you're running low on any vitamins because something like a deficiency in iron or D3 can make a person very tired/depressed.

It could be your meds, but don't rule out fatigue caused by something else. Trust your body, and make sure you're seeing a great doctor who can help you sort this all out.