Went to my therapist. Explained my symptoms. Took a few tests, got a diagnosis, fiddled with medications and dosages for a while, did some more therapy, and I seem to be in a good spot now.

Obviously, YMMV regarding the effectiveness of your treatment. I'm still sometimes up and down but the baseline is higher. Even if you decide not to take medication (it's not right for everyone and I won't pretend otherwise), do seek therapy. It's so incredibly helpful.