Time to go a little further back in time and look at either the first significant relationship that failed, or person who left you without an explanation.

With some relationships where there is not really a relationship happening, we see more into it than really is there and when it folds completely we are left wondering what happnened.

Focus on yourself rather than a failed relationship or perceived failed relationship...you will never find a reason if there was no relationship to begin with...

Hope you feel better soon