I literally had the same thing happen to me a few years back. I lost 40lbs and got to 298 and then gained it all back + more and had to restart at 370. Yuck! I never thought I'd get under 300 again, but here I am. You CAN do this! The thing that has saved me this time around has been MyFitnessPal. I started just logging calories. I wasn't cutting anything back yet, but getting in to the habit of writing everything down helped. Plus it showed me how much I was overeating. I was the super obese person saying, "but I don't even eat that much." Uh yeah.. it adds up quick! Once I figured out my calories I began to add in exercise. My best advice is to take baby steps. I feel like easing in to changing your lifestyle is more attainable than trying to jump in all at once. That's what worked for me anyway.