There is nothing you can do to easily or quickly fix that.
Though exercise is a good idea, the problem is that most people lack the motivation to keep going after the first couple of weeks. The gym is the very first thing you quit when you're pressured. I'd say try to do a group activity/sport. That way you don't only think about the exercise, but also about the people you'll do it with. And if you miss a training/meeting people may notice and call you to see what happened. So, it'll be much harder to skip.
Recreational volleyball is the first thing that comes to mind. But there are more groups/sports that you, personally, may find closer to your tastes. I once tried squash with some teammates from another sport and it brought us much closer. Wednesday became my favourite day of the week, not so much because of the actual sport, but because of the people there.
