How do you handle an anniversary of a past relationship?

My girlfriend left me about six months ago. She has bad depression and felt like she wasn't treating me right. What would have been out two-year anniversary is coming up, and I am really worried that it will set me off again. I just keep mentally repeating her name throughout my day as the date gets closer and closer, and I don't know what to do. I just can't shake the thought that we were meant to be together. But maybe I'm just crazy. I don't know anymore.