I'm the same way, though I've started to mellow out the past few months. Some things that I'd get pissed off about 6 months ago, I can let go of pretty quickly today.

I focused on why I'd get angry in certain situations and, more often than not, I realized it was because I saw a reflection of something I didn't like about myself in someone else's actions, and I resented them for reminding me of my own perceived inadequacies.

I do also sometimes get obsessed with worst case scenarios, but I try to counter that by thinking of how few of my worst case scenarios actually happened. It doesn't always stop the runaway thought train, but sometimes it's enough to hit the breaks and let it go.