Hi Eva_Michell,
Welcome!
Yes, isolation is a huge contributor to depression. I see you have social phobia, but if you can break through that at all, and find at least one other person to confide and befriend, it may help immensely.
Also, I am pretty isolated myself (and yes, it has really made me feel depressed), but I find that this forum helps to fight that. Over time, posting and reading forum responses help combat that depressive isolated feeling. I still think we need "real life, in person" friends (I am still working on that too), but for now, the forum helps fill a niche.
Welcome again and I hope you get a lot out of the program!