Sometimes GERD can trigger anxiety, since it can have a lot of mysterious and at times painful symptoms. The chest pain is often confused with a heart problem, but now that your heart has been checked out and is fine, you can stop worrying about that.
Rather than go down the anxiety pill path, you'd probably do better in the long run to just understand that GERD is often a life long problem, but not life threatening. That might help you to relax about it and not overly stress yourself out with worry. Just think about it, you thought you were dying on 12/31, but you are still here, so chances are you're going to be around for a long time to come.
Exercise is a very good stress reliever, but if you have GERD, you have to be careful how you exercise, or else it can worsen your symptoms. Basically you should only exercise on an empty stomach, and don't bounce around or bend over when exercising. So you might try something like riding a stationary bike for exercise to get you started again.
You should do the usual lifestyle changes that help control GERD symptoms, like modifying your diet, elevating the head of your bed, not eating close to bedtime, etc. And equally important is to stop worrying so much since that just creates more acid, and that will feed into your anxiety in a vicious circle.
You should consider seeing a gastroenterologist to treat your GERD, since they are much better at that than ENT doctors. They will probably put you on something better than Prilosec to help control your symptoms.