Like I start to worry about things so much to the point where I get very angry and frustrated over basically nothing

Like today, I had a three hour drive and out of nowhere, the entire drive I was so sad and angry. Like in my mind I got sooo angry with my gf for no reason, started thinking of all her negative qualities/cons, and was seriously considering dumping her

But when these happen it doesn’t even feel like it’s from worrying too much, it just happens 

Then I feel very overwhelmed and like im making negative progress with anxiety and depression and everything and being less happy. I find it hard to allow myself to be angry/sad without convincing myself im becoming unhappy and becoming depressed again