I know exactly how you feel, hun. My diet went totally out the window 2 weeks ago when I was in hosp myself. I ended up feeling so down that I considered quitting altogether. Stick with it though!
As for tips... if you're giving up the smokes, you're going to look for things to do with your hands and mouth - eating is the easiest thing to do. My advice is to try the patches, if you can. They are excellent! I tried them and after a week of not smoking, a week of hardly even having a craving, I had to stop because I was allergic to the glue
But during that week, I didn't eat all around myself like I did the other times I gave up smoking.
Other than that... try some Fybogel sachets... they're great for the bowels. I have IBS and they really work a treat for me.
*note to self* Take own advice, since you've been constipated for 4 days lol
Don't give up, hun. You may surprise yourself and have a really good loss next week! I had a STS due to the hospital and my routine being out of whack last week, and this week I lost 5.5lb and got slimmer of the week! Chin up x x