Just wish I could have the rational thinking ALL the time, not just some of it!
It is what it is man. It's going to take a lot more than just simply wishing and twiddling your thumbs. I remember reading your post you had posted earlier, about your workout and the neti-pot. Have you gotten into seeing a Psychiatrist? Personally I'm pushing that right now only because I'm new to the whole Psychiatry thing, and just the fact alone that I stepped into her office, I didn't feel alone....
I felt that if I was going to kill over dead, I would at least have some source documented... Crazy sounding but like I wouldn't feel that I would just die and nobody would know why. That's irrational thinking but hey it works. It eased the thought of my fears and worries.
The medication ain't half bad either, you still gotta struggle with it and you still gotta fight through it, there's no two ways around it. Worrying yourself sick IS possible. Stress can cause a lot of complications on the body, so simply take a step back and find things to take your mind off of your worries. especially with school and stuff. You might not think about it, but every negative impact that occurs to you (even an overwhelming state of mind) it's going to enforce a negative influence on your behavior and/or emotions.
If you're overwhelmed with a test, you might do poorly or you might overthink it, but as soon as you finish that test... regardless of how you did... you could straight up BOMB the test, you'll still have a release of that tension that you just took the test to begin with.
It's a lot to take in, but keep posting, and keep pushing yourself into a clearer, rational state of mind. even if you stay somewhat-rational... you'll soon acclimate yourself to becoming 100% rational.
If something is bothering you, drop what you're doing, and take a different approach.