I know you will probably not like the idea, but it may be time to apply for food stamps...and check with your local town hall about a food bank.
I used my town's food bank for a few weeks when my youngest was going through her major surgery (neither of us worked while she was going through treatment).

Is Marc getting free or reduced school lunch?

I loved your story about the karaoke night, btw...hope you have more fun days like that ahead (even if just speed-walking the mall with a friend)....