What do I do next?

Allright… this position sucks…epically… I know I’ve been in the same position in the very recent past…

Unfortunately the reality is that (at this time) its not gonna happen between the two of you, you’ve let her know how you feel and thats all you can do, you can’t force her to have any feelings like that towards you…

so you have two basic options…

One: it’s either dating the girl or nothing…

this sucks because like I said, it's probably not gonna happen (now) so you'd loose that good friendship that you've built up
the plus side is that eventually you'll get over her and hopefully find someone else

Two: stay on the side lines…

again, this sucks, sorry but its true, if you sit there with your feelings it WILL eat away inside of you, and is not healthy...
BUT if you take this method and play your cards right, and be that great guy, the good gentleman, you might convince her and subconsciously change her mind.

one thing for sure though is you do need to lay off, you’ve let her know how you feel and leave it at that… additionally whatever you choose to do it will not be a quick fix or resolution, so be ready for the long run…

just know that everything happens for a reason, whether you realize it now or not

hope I’ve helped! :)