Weightloss for Soon to be Bride

so my wedding is exactly 7 months and 10 days away and the panic is kickign in ! I have been engaged for 1 year and 6 days and have been on more diets than I can count since then. I've ordered my dress but would love to be at least 3 dress sizes smaller by my big day (the dress is reasonably adjustable). I cannot seem to stick with any one plan that works best - my various doctors have suggested everything from one extreme to the next low carb, low fat, etc. I can't seem to find any one regime that I can stick to longer than 2 weeks. I've been on Weight Watchers, Jenny Craig,  Nutri System, Atkins, South Beach, Calorie Count, Diet Detectieve (WeTV) and now Fitclick. NOt sure what is keeping me from meeting my personal goal - Ive tried logging, blogging and starving. Nothing is working. 

I work pretty hectic hours and have tried to incorporate exercise that I enjoy as a way to ensure tht I am eating but I always wind up hung up on small things - like missing meals and or not preparing them timely enough to stay in tact wtih my meal plan.

Does anyone have any ideas/suggstions or comments for me. This is a desperate cry for help but Im hoping that maybe something will stick.

thanks in Advance for your insight!