I can relate. Middle school and the first few years of high school were really tough for me. I wasn't diagnosed with ADHD until I was a freshman in high school, but it is so obvious in hindsight that I had it all along and my social life suffered because of it. I can totally relate to what you are saying about having two personalities. My ADHD really impacted my ability to make and keep friends. The older you get, the less acceptable it is to blurt out random comments, interrupt conversations, and overwhelm a group of people trying to just hang out together because you are bouncing off the walls with enthusiasm for whatever your newfound hobby is. I really began to notice that people didn't seem to want to be around me for all of the reasons I just listed. So I tried to tone myself down. I stopped participating in conversations. I would just observe other people and try not to get in the way. I wasn't ashamed of who I was. But I just didn't like the cold shoulder I seemed to get when I was myself.

It's better now though. I've learned how to socialize without completely becoming a different person. I do still have to be more conscious of my behavior when I'm around people that I don't know very well but I have been able to find that balance between being true to myself and coming off as socially appropriate.