What to do?

I've been in a very similar situation, so I understand what you're going through all too well. The first thing you want to do is to distance yourself from her. Not in a mean way, but you have to focus on letting yourself heal first. After a while, you should talk to her and ask if she would still like to be friends. Just because you're not dating anymore, doesn't mean you have to hate each other. She's probably moved on by now, and so should you. You don't have to find another girlfriend or boyfriend, but you should focus on yourself. Do the things make you happy or spend time with friends. You should have fun again. It's okay to feel sad or even angry, just don't lash out at her. She must have had her reasons for breaking up with you, but don't take it personally. Sometimes we don't get to have closure on things like this. Relationships, even good ones, can come to an end because one of the people don't think it can go any further. I wish you the best.

It's only awkward if either of you make it that way. Hell I was engaged at one point myself and it never worked out and she's living with her new boyfriend but we're still good friends regardless of what's happened in the past and I'm totally fine with that o/ It's fine to be upset about it but once you're ready just try your best to move on, be kind to yourself and treat yourself to feel better and eventually someone else will come along and sweep you off your feet o/ Oh and don't ever worry about your sexuality - you're you and that aspect will never change that :D