I feel terrible when I get rejected, too. Not just when it comes to the opposite sex, but in general. On the bright side, Jesus understands what we feel. And we can understand each other, too. =)
The most important lessons I learned from the Lord are (1) we are to love our neighbors as we love ourselves. The prerequisite to follow this commandment is to love ourselves, too (2) our beliefs shape the way we act, and our actions influence the outcomes. Hence, we see this theme of renewing the mind and giving our thoughts to the Lord so often in the Bible, i.e. 2 Cor 10:5, loving God will all our minds, etc.
Once we figure out which ones are lies, we can replace them with truth that we can find in His Word. Because we are certain that we can trust what He says, and they are grounded on unshakable truth. Eventually, when our beliefs change, so will our actions. In due time, our outcomes would change as well.
I will give thanks to You, for I am fearfully and wonderfully made;
Wonderful are Your works,
And my soul knows it very well. (Ps 139:14)
You are a wonderful person. It's not because of what other people think. But God said so. And God could never lie. =)