Identifying my ASD coping mechanisms

I have ADHD and don't believe I have autism, but I definitely have sensory overload issues. I realised I've had a coping mechanism where I sing or 'rythmically breathe' one line of a song over and over again. Unfortunately, people find this incredibly annoying and always end up telling me to shut up ☹️ With the overlap of symptoms it must be so hard. When I feel nauseous I'll tend to rock and repeatedly butt my head on something (gently though). I've assumed that all my neurodivergent symptoms are ADHD based, but I do things that I far more associated with autism before I read more about ADHD (lack of ability to pick up social cues, literal interpretation of speech, stimming). Sorry this isn't helpful, I'm more showing solidarity!

It could be. One of the hardest things I've found is trying to untangle the cause of each symptom, for lack of a better word. After a couple of years of doing research on my own I've figured out (and finally diagnosed) with ADHD, ASD, and cPTSD. they all present in similar ways but the treatment is very different. Like the difference between a tension headache versus a sinus headache from a weather change. I still have not found a therapist to help me figure it out. What you are describing could be grounding to help with ASD, or ASHD. It's hard to know without some more context.