I think your kids are just happy to be with you, and their concerns should be addressed. They need you to be happy.
Even when I had nothing, my own children were always a source of strength, and motivation. Even in the simplest of things, we supported each other.
Just give them love, and attention when you can't give them presents, or extras. You will more than get it back.
Have you seen a doctor for a check up, maybe some additional help is needed, family friends. The last think to do is isolate yourself from other human support.