too much on your plate? or is the plate simply not big enough?

I have this problem where I commit to things before thinking about it... I volunteered to work on Saturday, and realized this morning that I have to go to a play for class, and it'll take up about half my day to be there.  Now I have to go into work where they think I'm one of their hardest working and most trustworthy kids, and tell them that I spaced out and am actually not able to help them out.  This sort of thing drives me crazy, mostly because authority opinions register high in my stress level.

Frequently my grades or how a teacher views my class behavior and enthusiasm, is a very large stressor on my life.  Last week I got a 76% on a Spanish exam and I cried about it.  It would seem ok, if I hadn't remembered the fact that last year I would get 95% or around that on all of my Spanish exams.  This year is tough, that's for sure. 

Recently, there was a Times article in the Health & Wellness section about how we are our own biggest critics.  People tend to compare themselves to others so often, that we second guess our own abilities to function, whether it be in class, our jobs, or our daily exchanges with friends and families.  Not only am I someone that is always worried about what a teacher or a boss thinks of me, but I'm constantly worried about any friendships that I have.  "Is this person not talking to me for some specific reason?  What's wrong with me??  Are they just busy, or do they not like me?  Why don't they want to hang out this weekend?  Did they just blow off a text message, or do they not have time to answer it right now?  Maybe we're not that close anyway... WHY IS THAT??"           I drive myself crazy. 

No one can possibly be best friends with all of their friends.  My friend jealousy is ridiculous.  But it's there.  Maybe a lot of people have this.  There's a group of people that I go to church with, and I also know them from class.  They're all best friends.  I always thought that eventually I could somehow be in their group of friends because we had two common denominators.  But it never happened, and I have since then been wondering what it is about ME that makes them not so interested in having me in their group.  "Am I not Christian enough?  Am I not cool enough to be in the plays, therefore not cool enough to be in your click?"  I feel like it's a club that I have no idea how to get in, but there seem to be a lot of people in it. 
............Or maybe I'm just nuts.

I should stop whining, it's not like I have no friends.  I have pretty great friends, actually.  But again, you are your own biggest critic, and that means you come down hard.