Emarring problem...?

I know I've asked about this before, but I am feeling sooo bad about my flat chest right now. It's not so bad when I can wear a padded bra, but when it comes to swimming and relationships with guys, I am so embared. I'm 18 and can hardly fill out a 32 A bra (I'm not a cute perky 34 A or B, but rather completely flat). This next week I am going swimming (no choice about it) and I'm afraid I'm going to die of humiliation. I have a cute polka dot halter monokini with very slight cup padding but the halter opening goes down to the bottom of my chest. It's narrow, but nevertheless you can still see I have no ! But if I think this is bad, what about when I get into a serious relationship with a guy and he finds out how flat I am? How can I live a normal life and be self confident? The rest of my body is fit and in shape and I like it, but my chest ruins everything! I'm really worried that everyone will find me horribly ugly and weird because I'm so flat on the top. Advice please!