Make the day the best you can for your son, gather yourself up and do this for your child. Tonight, after he is asleep, you can tackle what's going on. You have to be the responsible parent now. Put it away for now. You need to help your son get over the disappointment of not seeing his mom today. That's the list of things to do.
I am so sorry. Do you need immediate help? Like some sort of hotline? I know there is a crisis thread on here somewhere with important numbers. I am worried about the things you typed.