Most Helpful Guy
While certainly there are guys who are mostly into curvy girls, TONS of guys like thin girls too. You may not appeal to EVERY guy (no girl does), but there's no shortage of guys who will like you.
in my opinion, if guys aren't asking you out, it's because you are putting out a vibe or displaying body language that says "I'm not interested, go away." If you aren't open, welcoming, and fun, guys aren't going to waste their time asking you out only to be rejected, so you need to take a look at your behavior. Ideally, if you could have a friend video you in a crowd, that would probably tell you everything you needed to know.
Most Helpful Girl
I doubt your weight has anything to do with it. There are probably other factors.
As for the guys who turned you down because they claimed you were too skinny, they are huge assholes who are not worthy of your time and energy.