I agree that your health is very important. I would say make a budget on the max that you can spend on groceries each week and stick to it. Now that I'm on my own, I have decided that I can spend no more than $75 a week or $300 a month on groceries. It doesn't mean that I all of a sudden have to eat junk but that I can't buy as much, that's all.
You will figure something out and you got some good suggestions already!