Was it your first true love? That one always bites the hardest!
The thing is, that grief is a part of everyone. And the heart actually does quite well with a good bit of scarring. Sounds odd, but that scarring is life itself.
You don't need to do much. One foot in front of the other... and you'll move along life's pathway.
But the memories are meant to stay... they form who you are.
The mind may dwell on all manner of thoughts, but the body urges you to move onward. Listen to your body.
It is brutal, and it isn't easy. So get help as Karen suggested. No need to be alone and battling by yourself.
You are not a lost cause