Oh wow, she dumped her child with someone who wasn't even obligated to take of it.

I can understand being naive and scared at the prospect of being a young mother, but it's like she has no conscience.

My best advice is that whatever you do, make sure you don't choose a path that will leave you unfulfilled and angsty. Let go of the past and try to understand the woman who gave birth to you. It sounds like she's just playing mother so that she can get rid of her own guilty conscience. If she doesn't want to build a proper relationship, you can't say that you didn't try. Move on.