Emotionally Down

I'm really immensely stressed and depressed now. There are a few things which leads to it:

1. the deterioration of my studies (main reason);
2. the feeling of guilt I have towards my dear friend who has just left to Birmingham;
3. wee bit of peer pressure;
4. lack of sleep;
5. surviving on only 1 meal a day;
6. some other reasons I would not want to mention because it may lead to unnecessary emotional posts

I'm no longer the boisterous, gleeful, confident, positive and joyous person people use to know. I am extremely pessimistic, gloomy, sensitive and incompetent at present. My goal in university and life seemed to be very vague in mind.

But, why? Why would all of these things happen simultaneously; at the time when I really needed extra confidence and motivation to do my work? The expectation of me to do well is just SO great! (from both my parents and sponsor) Seriously. I know the phrase "Just Do Your Best" sounds convincing. People keep telling me that "You'll do great, don't worry!"

I mean, it's really very sweet of them to have the confidence in me; but how would anyone know how well I will do? Honestly, no one knows how terrible my state is at present. I know myself best. And, I'm definitely sure that I'm NOT fine.

I really need to calm down. Was supposed to at least finish studying Digital Electronics by now, but I'm still staring stagnantly at the same page for hours. I seriously don't know what I shall do. I'm sad and lost.