You're only 20. Chill. Hard work pays in the long run. Your mental state is clouding your ability to focus, so try fixing that. Write down intrusive thoughts to deal with them individually. You already have the goals of more friendships and better fitness health, you just won't see immediate improvements, so break it down into manageable chunks. Log progress. To lose weight, 85% proper diet and 15% exercise. Don't leave the job simply on a whim. But if a job makes you miserable and you have other options then explore. You being young means you can wander further sideways in the cone of possibilities. We all struggle. Keep your head up and looking forward, there's not much else that's better to do.