Aww Becky, please hun stop giving yourself a hard time. You had a bereavement, followed by a nightmare of issues, followed by major surgery. Let up on yourself a while, things will get easier. Besides you may want to snack and nibble but it certainly won't be as much as you had before and when you go over the top you will know about it and won't repeat it!
Can you get your GP to refer you to a dietician who can just support you through the early weeks? I've got some info sheets from mine I can copy to you when I get back it might help you.
But like everyone says, a stall is not a failure, it's just your body adjusting and boy does your body have alot to adjust to at the moment, emotionally and physically.
Big hugs, am thinking of you and sending you lots of good karma xxx