Hello Smirfy,
I was first diagnosed with clinical depression when i was at University. I couldn't understand why, as I didn't think that I was 'depressed', however 13 years later, I can see how the upheaval of such a major change in life/lifestyle can have thrown me off balance.
I found the best thing was to be honest with my tutor and family. My tutor was great as were my family, even though I felt ashamed of the situation. I'm so sorry for you that you are not getting the same support.
You mention that you do arts, and I understand how this can affect you (I did a music degree). Occasionally though, the low feelings actually expressed themselves well through my art, and that helped me, not only to feel a little better about myself, but also to release some of the feelings. Hope that makes sense? Maybe, just maybe, you could do the same?
http://news.bbc.co.uk/1/hi/scotland/tayside_and_central/7084883.stm (this is a positive article :) )
I would definitely be careful about self-diagnosis, so I'm glad you are seeing a psychiatrist. If you are suffering from depression, you can convince yourself that things are much worse than they are, very easily!!
Be careful about placing too much reliance on the psychiatrist. I'm sure that they will be able to help you, but remember that stablising yourself from depression (or bipolar disorder if that's what you are diagnosed with) takes time. But you will get there ultimately.
I'm glad you've found this forum, as it sounds like you really need people to talk to, who are most definitely not going to judge! Don't feel like you have anything to prove to anyone, and try not to let your family and tutors bring you down further. Some people are just not in a position to understand.
F