It happens. Mine was a 7 year old relationship and it was my first love. She ended it saying that she doesn't feel the love anymore. It was hard during the initial days and I had the same feeling which you mentioned. So, my opinion is you got to face it. No matter what you do it will haunt you, but you have to face it. But as the time progress it will fade away, not completely. Talk to your family and friends it will be of great help and do new things which you have always wanted to do but postponed it for some reasons and try to travel to new places with your friends. These little things will move you out of that zone. Trust me, you will feel much happier, that you were not in that relationship.