constant thoughts.

so I'm not sure if this is related to ADHD or not coz I haven't been formally diagnosed. However these thoughts are making me lose my mind. It isn't even like a single topic. It's anything and everything and every song that I've ever listened too, every thought that I've ever had at the same time. There's always some voice or my voice in my head or some music playing. the songs that I listen to often, I've memorized them whole(without being conscious of it) and it plays in my head while I'm doing any task. It's gotten to the point where I don't actually need to listen to music to feel how it felt to listen to it? Like if a song is stuck in my head I just "press" rewind in my head and the song plays from start to finish. If that makes sense to anyone. The worst part is I can't stop it for the life of me. This is the same with conversations, videos, patterns and what not. Even while I'm studying sometimes I realize that I'm having a conversation in my head all whole focusing on the numerical I'm solving or whatever I'm studying. Am I going crazy? Does anybody relate?