I am so sorry you are feeling so low. I think we have all been there at one time or another. Things will get better, I promise.
My first suggestion is to check with your doc about taking an antidepressant. It seems to have helped a lot of people on this board. Sometimes we just need a little help to get started and then things will seem so much better. I'm on Librax for anxiety and it really helps me.
Second suggestion: Could your hubby explain to your daughter that you have tummy aches and that when you feel better you will play with her. Do you ever watch Sesame Street or some other children's show with her? My boys used to love that, especially if I watched it, too. You could even be on the couch with the heating pad but still be spending time with her.
Third suggestion: do you have any friends or family you can talk to or maybe that could even come over and help with your daughter?
Fourth suggestion: when you are in the mood for a subway (yummy by the way) and don't feel like going out, could hubby pick it up for you? That sure would break the pattern of boring chicken. Is there anything you can eat that can be delivered?
Fifth suggestion: do you have any kind of "treat" that agrees with you that you could eat. Mine is "Little Debbie marshmallow pie". I always have one around 8PM as my treat and boy, do I look forward to that.
Sending big hugs your way to feel better soon Barbie