Negatve thinking isn't easy to break, but I suspect this is just a small part of how it affects you.
You need to figure out how to deal with it, everyone is different, but you need to break the habit, because it's not just going to go away.
I go by this;
Can I change it? If not, there is no point in fussing about it.
Can I fix it? If not, there is no point in fussing about it.
Can I change? Yes? Do it, or shut up.
Can I fix it? Yes? Fix it, or shut up.
I don't know if you've realized, but negative thinking is -horribly- exhausting. It takes away from yourself in ways that are scary.
If you are incapable of pushing things you don't need in your head out, then I'd suggest a shrink. Crap like that leads to depression like a one way street.