Is something wrong with you? Not necessarily. But yes it is strange. If I had to venture an honest guess, I'd almost think that you have low self-esteem and "hide" in your studies and non-people related realms so as to not have confront your esteem issues.
And yes, it was the "i'm not pretty at all and nobody's interested" statements that triggered that. Of course, it is possible that you're just not interested in people. I have no idea if there's some sort of scientific term for that but I'm almost sure it exists. There's a condition for everything. However, I would like to say that I don't know how fulfilling a life you can live without anybody else in it to share some sort of physical and emotional connection with.
I'd also bet that you're prettier than you give yourself credit for. Granted, I don't know you and haven't seen you, but people have a tendency to undersell themselves. More people might be interested if they knew that you were interested in being liked by people. Of course, this is all on your own terms. If you have no interest in dating or anything then its all a moot point since, well, you can't win if you don't play the game.
But in the event that your lack of interest is rooted in your belief that nobody would like you anyway because of your attractiveness, then I'd say that maybe you should give yourself a chance. Don't take yourself out of the game. There's somebody for everybody. And you'd be amazed at who might show up if you let folks in.
We're all beautiful to somebody. And yes that was cliche and very "shiny happy people-ish" but it is also true.
You might be asexual. That means you can form emotional bonds with people but are not actually sexually attracted to someone. Now not all asexual people don't have sex, it just takes more for them to be sexually aroused. I would say start looking into that, and you might find some answers. Good Luck!
Maybe you need to get out there and experience things before you decide! Like when you don't know you're hungry until the meal's in front of you. It possibly is because that you're just not wired that way, but what's odd is that you don't even find yourself attractive so maybe you're holding back because you think it's better not to know what you're missing?
But it's not the end of the world if you choose your studying over your love life. As long as you're happy and content! And maybe later in life when you have a career and stuff you'll find time to focus on other things!
I wouldn't write yourself off just yet though, love can appear when and where you least expect it. I used to think I was going to grow up to be a crazy old cat lady until I met my boything. It was very inconvenient for my cat-keeping plans but totally worth reconsidering them!