I think I may be bipolar. Where do I go to get a diagnosis?

I’ve always kinda struggled with my moods and now that I’m older I’m starting realize that what I’m experiencing sounds like bipolar disorder.

I believe that I might be bipolar because there will be times where I feel so great, I’m energetic, I’m spunky, horny, I’m getting things done, and just feeling good overall. Then a few days later I’ll wake up feeling irritable, I’ll stay in bed all day, I don’t shower for days, I over indulge in food, I overthink, I have intrusive thoughts, etc.

It always seems like the bad moods that I fall into last way longer than the feelings of being full of energy and being happy.

Who do I talk to for help?