I know how overwhelming this can all seem. But know that you have been through this and gotten out the other side OK. Think of it like a broken bone - it is sore at the time, but is treated, and within 6 weeks you are on your way again.
I find I need to confide in someone when this happens. I will spend some time with a good friend who doesn't ask questions, just allows me to be in her company and she carries on with her life. I just tag along.
In the past I have also just refused to get out of bed, but you end up ruminating over things in your head, and spiral yourself downwards. Have that one friend you can confide in and who will drag you out of bed