I assume you mean 5 mg.
Get hard copies of your labs. Every time. Find out what your dr means by 1/3 back to normal. Some doctors don't realize how irrelevant TSH is at this point and are going solely by the TSH. Though that she reduced you is probably a good sign. I wouldn't go longer than 6 weeks between bloodwork.
I wouldn't panic about
a relapse. (Though I'm one to talk, I spent years waiting for the othe r shoe to drop myself
) ATDs can work, you just don't want to come off so fast. You may end up staying on a 5 mg. for a while, and that's fine. And after that, it might be prudent to halve the pill for a bit and then come off. YMMV. You'll see when you get there.