hey girl,
ive seen this in my life far too many times (ive never even dated because when i dont want a relationship they come along and end up being the worst thing ever, but when im ready for one, i screw up everything or they dont feel the same way, i GET YOU!)
honestly i will give you some advice that took me a long time to understand.
you are the #1 in your life. fall in love with yourself in really good ways. tell yourself whats good about you, and you will believe it. it spurs confidence. confidence is attractive.
keep your guard up, but also be lenient on yourself when you know what you want. everyone is different, and what i have learned is that when you let your guard down, if someone doesnt like who you are, you cant (and SHOULDNT) try to fix that, because you are you and there is someone on this planet that will adore the hell out of what you ARE. changing for someone could mean being miserable, and maybe you're with that person, unhappy, and you miss someone who would appreciate it.
basically love yourself, be confident, be happy with who you are, where you have come from, and dont change for someone else. i know frequent rejection and disappointment is hard, but man, look at the positives of life and love. you will get there!
smile