Basically you have developed low self esteem due to increased weight. I think you should start exercising as exercise is aphrodisiac to mental and physical health. Get Your thyroid checked. You have to take action, now or never. It's just one life.

Seek consultation with physician for evaluation of hypothyroidism, PCOD which can be the reasons for excess weight. Then consult a dietician and plan your diet accordingly...addressing your concerns and challenging yourself to overcome them is the only option to get out of your depressed state....also learn to appreciate yourself for your entire being and not just your physical appearance. Meet a psychologist for the same if required. Good luck