Struggling with managing anger

I probably wouldn't say I ever had "anger issues" but I could scream the house down as a child if I wanted to.

However, since I was 18 (now 26) it has definitely gotten worse. I'm more sensitive, I bottle things up and, perhaps even worse, I often invent scenarios so I have something to be angry about.

I am absolutely prone to exaggeration and making things up. E.g. today I wanted to just go out in the afternoon, as I wound up quite bored and with very little to do. I have my own car. I could have just gone for a drive but I knew it'd lead to a back and forth with my dad for ages explaining where I'm going and how long it'll take, and I've got it in my head (and I may even be right) that my parents won't be happy until I'm just not leaving the house on my own at all. Even though I have many times.

I want to practice singing in the house (not too loudly) but I'm afraid cos I'm convinced they'll tell me to shut up. Even though everyone else is able to speak as loudly as they want, my brother plays his guitar without getting shouted at to stop, my sister sneezes really loudly.

I'm having therapy and my dad said that he and my mum know me more than a therapist would and I interpreted that as them telling me to stop therapy. Which really angered me.

I get probed occasionally when I'm on the phone to someone, or when I used to go out and meet friends. They'd demand every detail. I don't have any friends currently and this makes me not want any for the rest of my life.

I don't know how much of this is in my head. I know I can't assert myself but it's also very very easy for this to bother me. It feels really unfair and it doesn't get any easier.