You hit the gym.
First of all, the irony of having to drive to the gym so you can walk on treadmills, or cycle on stationary-bikes to go nowhere, or lift weights to put them back down, never escapes you.
Second of all, you have this looming thought that maybe--just maybe--there's a way to make this walking and cycling and lifting session useful somehow. Like maybe cycling/walking to an actual somewhere? Or lifting actual bags of groceries? But no, instead you just feel like you're driving in place, or in a simulation (simulated walking, simulated cycling, simulated freedom of driving, ...).
In the meantime, you tried absolutely everything to keep your weight down. Weight loss programs, weight loss milkshakes, dieting, gyms, fad diets, etc. Absolutely nothing works--gyms just make you hungry; dieting just makes you crave for more junk foods. Starving just makes you fall sick more. Your weight falls, then goes back up.
Back to actual cycling. Use the sidewalk or take the road. Does it really make a difference? You crave the outdoors, not the act of exercising. Exercise is a mere side-bonus.
Or just be stuck here indefinitely.