Do you have a GP? They can diagnose you.
Perhaps check out some websites and see if you think you meet the criteria, wikipedia is good, studentdepression is a UK one and quite good.
http://en.wikipedia.org/wiki/Clinica...s_and_symptoms
A GP could prescribe you anti-depressants or give you other forms of help to try make you feel better. :)
Perhaps also looking up social anxiety disorder on wiki? Like I said, I had them problems with my friends and my doctor diagnosed severe social anxiety.
Hope that helps in some way, and that you feel better soon.