My roommate watches and judges me. Any help?
This roommate, whom I'll call Christian, is a young black guy, same age as me, and is pretty intelligent. However, he's kind of figured out that I'm not a very social person: I don't ever "go out" on weekends, have relatively few friends, and spend more time by myself than not. During the weeknights, when I've gotten home from my internship, we're sort of okay together, since it's accepted that everyone's tired and just wants to hang out. But on the weekends I run into trouble.
I'm not sure why, but Christian seems to have locked onto my lack of social skills, and is acutely aware of what I'm doing at all times, usually being judgmental about it as well. He always asks me what I'm doing, where I'm going, what I'm cooking, who I was hanging out with, etc. He mocks me sometimes, too, which I'm really not okay with. ("What am I gonna do with you, [my name]? You just sittin' here alone.") The other two apartment residents are often gone, so although Christian is out and about more than me, the time we spend together in the apartment can feel excruciating; I'm just waiting for some little jab about something.
To combat this, I often go downstairs in the complex' common room area, mainly to study/read/play games alone or sometimes just to watch TV. But recently, Christian has started to inexplicably appear down there, if only for a minute or two; he'll usually say something like "Wow what you doin'?" or even just stare at me for a moment. After he's gotten his point across (I don't do anything fun, I'm alone, etc.) he'll just as suddenly exit, leaving me humiliated. I do know that he goes to clubs and bars and all that, but he's always vague about it when I (quite rarely) ask and usually brings it back to me.
This Saturday, he was boasting about how he was "going out" somewhere. He kept asking me if I was "going out" anywhere, so I finally told him "sure, maybe, pretty soon I think." A definite lie (I'm underage and won't get an illegal ID) but it seemed to placate him a little. Except... voila! 50 minutes later, he bursts back in the apartment (he had "forgotten something" before he left) and quickly found me in the back room. More passive-aggressive taunts, and then he leaves again, with me feeling absolutely horrible.
Even when I'm inside these individual classrooms they have in the downstairs area, he'll pop into one of them under the pretext of talking to someone, then look around and find me, then say his usual stuff. I don't know how the hell he's finding me like this, but I HATE the feeling that he's constantly aware of what I'm doing and where I'm going. I may be completely paranoid here, but this whole thing feels very judgmental to me. Plus, whenever I come back from somewhere to our room, he's never there... except he somehow always appears 20 minutes after I get back, usually asking me if I've "been here all this time." I can't stand it! Or whenever I go grocery shopping, he will ALWAYS notice somehow - he'll see the new stuff on my shelf, or see the plastic bags, or the receipt, and then interrogate me about where I was. I'm okay with having a diminished social life, and even okay occasionally leaving the room to give the appearance that I'm doing something, but I don't know what to do when my roommate is almost spying on me like this. He's extremely, extremely aware of everything I do, and I'm slowly folding under his withering stare.
All I want is to be left alone sometimes. To avoid looking like a loser, I vacate the apartment sometimes and go visit local museums, monuments, arboretums, etc. I've dealt with that before, and that's okay. It just seems like my roommate's going out of his way to repeatedly humiliate me and draw light to this. Any advice?