hello and welcome,

i understand your struggle.
i think it's best to stay away from caffeine and any drugs.
i'd stick to the basics. eat less, portion control, less carbs and more fruits and veggies.

i believe on the exercise regimen that you could find a place that you can tolerate. back off the running and walk, or walk fast. if you find you can handle 10 minutes start there and work up, gradually.

as time goes on you'll be able to work up in length of time or advancing to a more physical type of exercise.

water sports is good during the summer.
biking is great too.
try to find something that a bit of fun.

good luck.