For one thing you are in the process of greiving. You have to give yourself permission to grieve. It is a process and you jump back and forth through various stages of grief finally getting to acceptance. There is no time limit on grief.

I was once in a six month relationship after I got divorced. I thought it was the real thing. I was madly in love. When she broke up with me I was devastated. It took me a year to get over it. I became obsessed with getting back with her. I realize now it was just a rebound relationship, a bandaid.

Also I realize now that when she broke up with me it brought up alot of abandoment issues from my past that I didn't even know I had. Thats why it took me so long to get over it. At some point during that year I realized that it really was not about her breaking up with me but that I had to really look at my baggage from the past.

The next relationship lasted two and a half years and when we broke up it only took six months to get over it. I had to grieve the loss and sense of rejection but it wasn't near as bad. Maybe the end of this relationship is a big trigger for you for past events.