Please, please help. I really don't want to be like this anymore! I don't know what to do?

I've always been like this, but it's come to the point where it's taken over my day-to-day activity and it needs to stop. I worry way too much, and now it's a burden. I'm constantly worrying about something, someone, the reasons for someone's actions. I overyze situations and I arrive at conclusions that when I tell other people, they find them absolutely illogical and unreasonable. When something happens that I deem to be a sign that something is wrong or something that merits worrying, I freak out and I feel stressed and worst of all (this started happening recently), saddened, and nauseous as though I had a huge meal and it's slowly rising back up my esophagus. It's hard for me to forget it, not worry, and distract myself b/c as hard as I try, I find myself slipping back into a frantic, panicked, nauseous state. Worry hangs over my head like a dark cloud that won't go away until I've (to me) solved everything. For example: I was worried recently that my boyfriend was angry with