I'm sorry that you're feeling foolish. I agree that writing is a good way to channel and express your feelings. For whatever it's worth, I don't think you actually ARE foolish. You wanted this person to have a happy, healthy, full life - which is good - and she was unwilling or unable to respond to you in the way you hoped - which is less good - but that doesn't mean you were wrong to want good things for her. It is a wonderful thing to be able to appreciate the beauty, wonder and majesty that is another human being. The world needs more of that, not less. It is, regrettably, not a paying job.

Perhaps check back with her in a few years, to see if she feels the same. Until then, yeah, carry on with life write. Maybe try to love other people. But please don't decide that your ability to love was not valuable or good. Even if nothing came of it this time.