Thanks for everyone's replies
My self-esteem has always been low. I guess I usually don't feel really good about myself physically. I'm overweight

and never seem to be able to lose any of it. And then I find out the guys are into cute, thin girls, so no chance for me there =\ I would like to try therapy, but I always seem to find an excuse to put it off (no money, time, etc).
I guess I see a lot of the downsides in relationships (friends always complaining about their boyfriends, breaking up, my parents arguing and stuff). Nothing too traumatizing, but then I see my cousins and some friends all happily married with kids or have girlfriends/boyfriends and I feel left out maybe? I should probably just boost my self esteem first before thinking about this stuff