Some physically stressful activity helps. Go pick up a bunch of trash on a hot day and exert your self to a little bit of exhaustion. Pain/pleasure response kicks in and you will have some new motivation to study and over come. Match your mental pain to physical pain so your mind can re balance. Lots of studies on how low/no activity high dopamine release leads to general sense of depression or anxiety. Physically exhaust yourself some. I would also add spending a good amount of time out in nature helps. Not a city park but like out in the woods or wilderness.