My story is similar to some of yours. A lot of social and romantic rejection since I was young has made me terrified of falling in love, in case I get hurt/rejected.
I'm quite a sensitive and emotional person which doesn't help either. I've only recently learnt to be friends with men, but if they show the slightest interest in me - esp. if I'm attracted too - I get very nervous and blush furiously. I just want to run away and hide.