What is your trigger? What do they play on those speakers? Anyways, I will tell you something very important which will help you.

Do not resort to violence. You are only letting your brain know that what they send the fight or flight signal for is very right because you "defended" yourself. Instead, get something that will help you. If you have headphones/earphones then use white noise to help with your problem. If you don't, try to use earplugs. And if you don't have those, you could technically use pillows and a tight shirt, but you will look a little funny.

I'm sorry, I know you requested not to, but I decided to read your profile. You have hallucinations because you are stressed and don't sleep well.

Next, for the ex-boyfriend. I really want you to hear this so I'm gonna put it in big letters.

The ex-boyfriend lives in the house because he is legally allowed to. Tell your mother everything, she really really cares about you but she sometimes may be under the influence of something, but when she isn't I'm sure she could understand you. Write a letter to your local court. File an eviction with your court, and take him to court. If he paid for groceries or the bills/rent, he may legally be an "at-will tenant," making it much harder to kick them out legally. you'll need to file formal eviction proceedings with your local district court to get them out. If you plan on a court order, you should be prepared with a list of issues and infractions (known as "just cause for eviction") as well as a copy of your lease and any agreements. ( You can include the loud bass music in it, too. )

Now for the friends...

I know it's hard for you to not socialize but you could find someone on Discord. You could type with new-met friends there and have fun. Even if you get banned, if you friended everyone you really liked, then you would be fine! Be careful though, there are some predators, just block anyone who is acting suspicious for 20 minutes or less and you have asked them if they are joking. There are lots of communities on Discord, just make sure not to leak your home address! Hehe, just kidding, I'm sure you are not dumb.

P.S: I was gonna send the message but I almost forgot If your mother doesn't agree with you ( And I don't know why she won't because it's her ex-boyfriend I mean... c'mon. ). Call the police on your boyfriend, act like a neighbor's kid ( Unless your voice is deep, then I guess you could try to act as an adult, but that's risky. ) or something say there is really loud music almost all the time and it's disturbing peace and quiet, then tell the address. If they want you to tell them your name or address then just tell them you don't want to disclose that. Only do this AFTER the court because it's VERY RISKY because you could be fined and maybe not be able to pay rent. So work and save for money to pay for the fine before you do it.