Hi, Paula! Don't be so hard on yourself. This stuff is not easy at all. Needing and craving food is one of our basic instincts and you're asking your body and your mind to go against it. Realize that sometimes it may or may not be possible, and if you cannot fight it, you may be able to "reason" with it.
Honestly, I fight the "urges" by giving in to them, but not really. I give in, but before I do, I make a "deal" with myself to have only certain amount of the "bad" food. And then I make sure I enjoy every byte of it, and when I'm done, the craving is gone.
Anyway, I just hope it helps any.