My inability to understand what is going on with me is making me depressed.

Over the last few years I've gotten cloudy. I can't think or remember things very well. Simple situations like job interviews or going to meet with friends at a place I haven't been to before make me very oddly nervous. My friends care about me, but are becoming more distant. I'm different around them than I used to be. My fiance loves me, but I always find myself unable to communicate most anything that I feel to her or anyone else. I can't feel comfortable, like I'm always getting ready for something, testing myself and everyone around me. I feel silly doing this, but I've recently taken a skills and personality test for a job promotion, and was refused the promotion based solely upon my personality results. I think it may be time to admit that there may be something wrong, and it's getting worse, in my head. I'd certainly welcome a recommendation. I'm pretty confused. Thanks.