soberred,
Hugs, I am going through the end of a 25 yr marriage, and it's painful and terrifying, devastating. At first. But time heals if we let it, if we let honesty and hope seep in.
I have to calm myself down and listen to wise friends who have my best interest at heart and who know me. They tell me they know that I can get through this. They tell me honestly what they saw in the relationship, and that it's passing is not necessarily a bad thing. They tell me the strength and resources they see in me, and that I have in my life.
Think of what you would tell a friend in your position. Then be your own friend and tell those things to yourself.
I read this somewhere, and when I start getting too worked up over something in my life, I remind myself "think of what a hopeful person would do in this situation, and try that"