Oh, my, Mary-Lou, you sound discouraged.
I wish I could say something to make it better, but I have to say in my experience over the last 16 months, I've hit one plateau after another, again and again. Sometimes it seems I manage to lose a couple pounds when I didn't try, and other times I swear I was eating exactly what I should and exercising right, but my weight stayed the same. Those days, I was almost ready to say, "the hell with it" and go polish off a pint of Haagen-Dasz double fudge.
All I can say is I hope you stick with it, and keep going. Four weeks isn't very long to be on a diet. It takes quite a bit of time for the body to get rid of pounds, especially for folks like us who aren't 25 any more.
You know what you need to do, just keep going and have faith that in the end, it will be worth it.