Always angry

I’m not sure why I have so much anger built up, it’s actually been like this for the last 6 months. It’s so frustrating because it really affects my relationship. I’ve never had a short temper, but I’m so mean towards my bf. If he takes 10+ minutes to respond when I know he’s just sitting on social media it drives me insane & I start an argument. I know in the back of my head it’s not that big of a deal, but I honestly feel like I can’t control it. Ugh😕