Not quite sure what's going on here...

Hi.I wanted to ask everyone's opinion on this, because I'm not quite sure what 'this' is...I'd like to start by saying I have no major issues in life, I haven't got any problems with family, personal relationships or friends. In fact I have plenty of friends, a boyfriend, I'm at university, I work my arse off during the summer, so I'm not even hard up.But for the last 6 weeks (since starting uni for 2nd year in fact) I've felt different, usually i'm very happy, I walk around with a grin on my face, but now I only occassionally have that, the best I can describe it as is a black cloud, I will be fine, then the black cloud is blown over my head, and it's difficult to get rid of, I feel like crap, I dont want to talk to anyone, I dont want to go out, I feel lonely, I may even burst into tears. I have no motivation to study, practise keyboard and I feel guilt for it.Also since I can remember I've had some paranoia issues, believing that if i'm out the room i'll get spoken about and that anyone connected to me has an ulterior motive. I've often felt like a strange feeling of inferiority, but also with a massive ego thing behind it that I cant quite back up, i dont really understand it, it's difficult to explain.Thanks for reading, I dont feel like I can talk to anyone too close fully about it. although i crave to. I feel like a complete drama queen because I dont have problems to back up this bizarreness with, so apologies for that, I'm not trying to take the piss. If anyone can give advice or something please do!Love.