I've recently been mourning the end of a friendship and I've found that this technique, which I came up with after prayer, helps a lot.
First thing is to feel the emotion that is troubling you- feel it in full, The idea is to get beyond the drama, get beyond blaming, or guilt or analysis, just calmly and honestly feel the emotion, even if it isn't socially acceptable, even if you yourself don't approve of it. Just feel the emotion in the purest form. Then express it mentally to the person who you feel the emotion for. Do it in a spiritual way. Be honest about your feelings and don't allow any drama, excitement, debate, judging, blaming or analysis to get in the way. Just pure, honest emotion straight from the heart, not blaming the other person, not blaming you, but just saying and feeling how their actions have affected you. Feel the emotion to its fullest. Then "send" it to the person in question. Imagine that these feeling can be sent like a letter, or an e-mail. Or just send it off into space- like an unwanted package. Puff- it is gone. This should make you feel better already, and even give you new perspective on the situation. Then follow it up with the wish to rid your body of all bad emotions. Just imagine them all rushing out of your body. Pray that all the bad stuff gets washed out so that you can be clean and pure and free again. Then rest. You may be a bit shaken up by this if you have come in contact with the divine but either way, you will feel better and in more control and you'll be able to function again.