Am I becoming anorexic?

I'm 20 and at 5'6 I've lost 5 lbs recently in 3 weeks from my 132lbs from not eating as much. I wasn't intending on shedding food so much, but everyday I like what I see. I like that I can see my progress. I'm scared that this isn't the "healthy" way(working out and eating the right foods) to lose weight. I went out to dinner and people commented on how little I ate, but I realize that I can't eat even when I want to. My stomach shrank to a little less than a cup full of food until I feel full. I'm still at a healthy weight, but I'm just nervous that this could get worse.

Part of me just wants to keep going until I feel like I look skinny enough and then just go on normally, but then part of me is afraid that I might actually develop a real problem. Even eating a small bowl of noodles give me the ever so faint feeling that I'm going to puke.