I am always worrying , how can I relax ?

I'm always worrying about everything . For example I'm worrying right now about being late back from lunch at work , so I shoveled my food in and now I have nothing but a tummy ache and 12 minutes left. And this morning I got mad at my boyfriend because he was being slow and I didn't want to be late for work, I ended up being 30 minutes early . I'm constantly  worrying, not just about work but about everything . How do I stop ?!