I've been there too and letting go is never easy. I eventually broke down and was admitted to hospital. At the time I was not on anti-depressants. Are you currently taking and seeing a pdoc? Maybe phone your doc and explain you are going through a very stressful time and need something to help you cope. I have Benzo's I take when I experience real anxiety and feel I cannot cope - it slows everything down and lets me calm down a bit more.
It's also very hard to be friends straight away. You may need to give each other space apart for a while, and only start your friendship anew once you have really dealt with the reality that it is really over.
I commend you on making such a difficult to decision - strength to you xx