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