Dear Jill,
Much of your suffering is due to thoughts of remorse, thoughts of where you might have went wrong, thoughts about what things should be like, etc. This moment, absent of the drama created by the mind, how are things?
Be still of mind generated memories, thoughts and drama. Be silently present with the raw sadness, void of story and judgments. Feel what it is to silently be alive in this moment: the feeling of breathing, the weight, ache and tingle is different parts of the body. In other words, be kind to yourself, get out of the story in your mind, and into the present moment of existence.
Cry your eyes out. Go swimming or running. Do these things with a silent mind, with attention placed on the actual senses of doing these things. Learn to differentiate between the minds tight agonizing drama, and the openness of reality. Rest in the warmth of silent existence and life. Use the mind only when you absolutely need to, otherwise be more and more present with the sense of life in and around you.
You'll get through this. This too, will pass. Use this troubling time to help motivate you to be grounded in reality.
j