Thanks for the replies guys.
I did further research and found that I'm not schizoid after all, since I don't meet all the requirements and my issues aren't at the high degree of severity required.

HOWEVER, I took purple_fin's advice and took a look at depression, and came upon Dysthymia (aka minor depression) and it describes me so perfectly, I was freaking out. The symptoms that matched included social withdrawal, irritable hostility, conflicts with family & friends, a parent with major depression. Plus, I've always felt that I've never been truly "happy", which is very common in Dysthymia.

It's both a relief and a sadness to have found what I'm actually suffering from, along with my OCD. :/ I really don't know where to go from here, but perhaps I should consult with the depression board? Thanks again!