You don't have to be sorry about anything. This site exists for a reason, which is to meet others with SA and share your experiences with SA to get help from others. There's absolutely nothing wrong with venting out your feelings.
Anyway, I agree with you. Keeping up with high expectations isn't something I'm good at. I'm kind of going through the same thing at school right now. I act very social around my friends but in reality I feel very depressed and angry in that school from all the stress and a-holes but I act happy and social around my friends so that they don't worry about me. Having people worry about me or pity me bugs the heck out of me.
I have a feeling that pretty soon my innermost feelings are going to be released, in a very explosive manner on top of it. The stress is becoming very unbearable and I know I'm eventually going to lose the few friends that I have because of it. But hey, that's just life I guess. My best advice to you is to stay strong and go along with whatever you think is best for you. Not the greatest advice ever I know, but I don't know what to say since I don't even know what kind of advice I should give myself on this kind of situation. In any case, I give you my best wishes and hope things get better for you.