i hate myself...

I'm really a goal oriented person. When I say I want to get something done, I'll do everything to make sure I get it done. I'd plan my stuff properly, work ridiculously hard and have my mind set on a positive mode. And when things don't go according to my plan, not surprisingly, I get really upset with myself. This has happened to me throughout semester 1 and I'm currently suffering my first bout of depression for this brand new semester (and today's only the fourth day of the semester). I wonder why can't I just stop thinking so badly about myself. I have learnt enough that setting unrealistic goals are just stupid. The goals I set for myself now aren't too much to handle. It's just things like contributing stuff about pneumothorax, PSTD and bystander intervention in today's PBL, yet even that I couldn't do it. I was just so quiet. Though I'm quite sure the people (my new PBL-mates and the tutor) won't make judgement about me based on this session alone as I've proven myself to be quite a bubbly, intelligent and reasonable person in other occasions, academically and socially. I simply feel unsatisfied that I wasn't even able to get my ideas across the table, after spending one whole night awake finishing my PBL work, which makes me even angrier at myself. And I told myself if I don't understand something, unlike the last semester, I would ask. But now I'm behaving just the same, no courage to ask my tutor/lecturer/demonstrator things that I'm not sure of (well, as a consolation, at least I managed to ask Dr Tracey a 15 second question about the FEV thing just now..). Then I thought this may just not be my lucky day, everyone has these days... and I really ought not to feel down just because today isn't my lucky day. I can rant on and on about the many positive reassurances and alternative points of view I tell myself, yet it's just the down feeling that won't go away. I don't feel I have control over myself anymore these days.
I had a really fresh start for this semester. First day of PBL was great, even most of the stuff I talked about was rubbish. First dissection was good.. thoracic anatomy that I crammed in the night before (until 3:30am) manage to come out of my brain during the practical. I loved my teaching session with primary school children yesterday, felt that the kids really enjoyed it too. Then I went for judo, which was so much fun that I wanted to share every single detail here.. the endorphin lasted for almost 1 day!.. but now I've just spoilt everything. I don't feel like thinking about anything anymore, even the good ones. Just feel numbed. I hate myself.