First off, I am learning more and more that "normal" doesn't exist in the way we think it does. For each person it is different. It seems in reading your post that you have several periods where you are feeling anything but "normal".

I agree that seeking medical help in determining what might be the culprit is a step you should consider. I also know that until you are ready to do so, we can ask you to seek help until the end of days but ultimately you need to make that choice.

I can offer only to listen, to offer my advice, and to hope that you will have brighter days. I have felt the way you have, known the despair of trying to figure if it would be worth missing that upcoming turn as you speed down a road, known the euphoria of being on top of the world just because I am amazing. These all passed and now I seem to just hope I can stay even keel for more than a few days at a time. We all have our struggles and you are taking a good step in joining the forums to search out how others deal with said struggles.

Good luck