Do i have ADD or another neurologic disorder ?

I have been trying to discover what i have for years now. I am 22 with a very big problem on focusing... its been a problem since i was very young. Its two different things that might be part of the same problem- let me explain- when i was younger and in school I would zone out completely; my eyes would blur and i would have no recollection of what the teacher was saying or anything. I would always tell myself "ok gotta keep focus" but 5 minutes later i would completely zone out again. It was almost impossible to focus for a full hour in class and would make my grades suffer. Then at home what would happen is i would act out scenarios- meaning i would pretend i was talking to someone about something and just have a full on conversation with myself. I would even have to run to the bathroom and act it out in the mirror so no one can see me. It can be a funny story im having with myself where i would crack up alone or it can be sad where i will actually start tearing. I once read something about over imaginative ADD but im not sure. Most of the time the thoughts in my head are racing and are just too much for me where i become EXHAUSTED. If im alone throughout the day im just exhausted to the point where i have to nap because of all the thoughts and scenario plays. I try to tell myself to stop but it continues. Marijuana seems to ease this exhaustion and helps me calm down but im not one to smoke all day just at night when im exhausted and just need to sleep. I have always had trouble sleeping also. For about 2 weeks in my college career during finals week i was taking some adderall where it was like a miracle pill for me. When i was on the pill i said to myself "This is how im suppose to be, this is how it feels to be normal" It felt like i was a genius as well, like if i didn't have those racing thoughts and lack of focus i can really be amazingly smart. I stopped taking the pill because i figured it was unhealthy for me since it wasn't my prescription. Does anyone know what i may have ?