I think I am neurodivergent with sensory issues, and that causes anger issues in me. What do I do?

Hi, I need serious help.

I've noticed that I get extremely angry and turn into someone I don't recognize when I am faced with multiple simultaneous auditory inputs. This includes people talking over each other, or even someone trying to talk to me over the TV. I always get irritated and have to pause a movie if someone is speaking to me, or if I'm having a conversation, to give you a few mild examples. I know these are signs of neurodivergence, and I've exhibited multiple others since college, but I don't know what to do about it. I'm very particular and get sensory overload often. Since the age of 19/20, I've wondered if I have either ADD or ADHD. I'm a psych grad but not clinical, so I don't know how right this is.

Recently, I keep snapping at people more and more. What happened today was unforgivable and what led me to write this post. I chewed out two girls in the theatre because they were talking loudly. I don't even know how to justify what I did. They were just teens watching Spider-Man, yet I could not stop thinking about what I was going to say to them and getting really angry. I knew they were sitting in seats they didn't pay for, so I even thought multiple times about telling security just so they'd stop disturbing me. At the end of the movie, I walked up and told those girls that at their age, I probably also wanted to sneak into the back row, but they should have the decency at least to put their phones on silent and STFU. This is the worst part - I tried to take a picture of them to show the mall people, but my flash went off, so at the last moment I covered my phone. They definitely noticed.

This is not like me at all. As soon as it happened, I walked out feeling so ashamed and really embarrassed. I can even remember my thoughts during the movie, and how frustrated I was, but now that I'm back in my room typing this out, I can't even believe I thought like that. It's like I came out of a haze. Taking a picture of them? What would the security people even have done? Why did I even try to do that? It sounds stupid and dramatic, but I get so angry; it's honestly like I turn into a monster I don't recognize. I know apologizing and acknowledging doesn't justify it. I didn't even want to type this out because I know what I did was so wrong, but I think I should be honest and take accountability at least.

As a 25-year-old currently living with her parents, how will I go out and get tested? And even if I do, what will it change? How do I regulate these emotions? Has this happened to anyone else?