I agree with many of the thoughts brought up here, go to the Con with the mindset to enjoy, and then do so. Talk to random people (I have trouble doing this, but I'm getting better), and engage in some conversation. You already have one thing in common with most the people there, Anime! Talk to people in costume, especially the series you like(again, a shared point of interest). Ask them how they put it together. Many of us are more than happy to go into vivid detail as to how it is done. Find one of the hug lines, go through it then join and give some back. A great way to meet people and will cheer you and them up. Getting hugs feels great, giving them even more so. If you are going to go solo, bring a camera and do a photo safari. I personally love this as I get immersed in the Con, yet do not need to talk to much. A lot of asking, can I get your picture, or oooo, hold that pose one moment longer. There is so much to do, and while you may see her, you can also be civil towards her. If you were friends before your relationship, it is possible to stay on friendly terms after. Treat as you would meeting a new person, standard greetings, inquire to their health, you know, really basic stuff. I've had several relationships with friends that ended in break-ups, but after some time, we were able to go back to being friends.