Suggest Diet And Exercise For Weight Reduction

I m looking for a dr. in the Spring Tx area that will prescribe Phentermine. I am 248lbs. 5 8 , 51 yrs old. I have never weighted this much. I have a lot of stress, high blood pressure, anxiety and sleep issues. I was in 2 car accidents in 2006, which resulted in neck and back surgery, which caused peralises in my left side. I just want to get this weight off, I have tried to diet and only lose maybe 3 lbs and then that is it. Thanks for ay help you can provide.