That voice in your head telling you negative stuff is often the culprit of bad feelings. The key is to not just stop it, but to replace it with some kind of positive visual, mantra, or saying that will help you be in the moment. LPH has good advice. A few years ago I had to build back up to my previous level of endurance. I did lots of errand rides, going to farm stands, and riding to appointments. I still rode on the weekends and occasional fitness rides during the week, but I had to enjoy the present of each ride. Those little miles added up. I also went to yoga classes. The key is to have realistic, but fun expectations.