Sorry you are having problems on Lithium. I had similar and more side effects.

My main advice is to not give up on trying different meds. You might have to try MANY different meds to find the most side effect free ones. I tried almost all mood stabilizers till I found one that works for me.

Also, take the medication consistently. If you start to feel better, still take your medicine. Going off it can cause symptoms to return.

I was in denial of my diagnosis for probably ten years then had a terrible bout of mania and depression. Then I realized, wow, I really am bipolar. I think this doubt is common because who wants to have a chronic disease?