I Need Some Reasons to Not Give Up

Hello. I am not obese, but I've almost always been overweight. I am currently about 40-50 pounds overweight. I have three young kids and I've been trying for years to find the right diet for me. I know that they all work if you can actually follow them, but I have a serious problem with sugar dependence. It brings my efforts to a screeching halt every time. I am prediabetic, if not diabetic already, and I have borderline high blood pressure. I am a nurse and I know what I should be doing, but the desire for sugar overrides every piece of common sense and knowledge I have. I've tried curing my problem with consistent protein, but I don't really like most protein sources. I had chicken for breakfast this morning with half a grapefruit because I wasn't in the mood for egg whites. I am literally not interested in any of the foods that are supposedly the ones I should be eating. I am really losing hope that I will ever overcome this problem. I can't even go one day without the sugar (mainly chocolate), and once I eat some, I always eat more. I can't moderate because it's a compulsion. Please tell me if you know of anything else I can do. I've considered a fat farm or something of that sort, but I am needed at home and I probably couldn't afford it anyway. I don't mind exercising, but I've learned that it does very little good if I'm not eating properly as well, so I've stopped doing it. My eating has always been the unsurmountable part of becoming healthy for me. I lost 30 pounds in 3 months when I was 17 by using Phentermine, and that is the only time in my life that I have lost a significant amount of weight and kept it off for at least a few years. I've tried using it again, but it causes palpitations and hypertension, so I can't use it anymore. Can you help me? Can anybody?