Lol harman no
MN can be a godsend - friendship at the end of the computer and companionship - particularly if you're home alone. But if you're missing out on sleep lurking here when you should be getting rest so you can deal with DCs, then that's not ideal.
If you've had 4 kids, you're not likely to ever be the skinny minnie you were before but you can increase the good things you're eating - fruit and veg and cut out things that are going to make you feel bad in the long run. Yes, I know that the packet of crisps/ chocolate bar feels good while you're eating it (I know, really I do) but you feel rubbish afterwards so it's better to go for the healthy option.
I really think you're brave coming on here trying to get things sorted but perhaps the key is to do things slowly - work on your diet and smoking and then cut down on the drinking for example.
Have you seen your GP
How old are your dcs?
Sorry lots of questions.