Intellectual stimulation shouldn't be too hard to find. There are always books, documentaries, movies, art galleries, museums, websites, newspapers, podcasts, conversation, classes, study- what are you interested in?
As for sensory stimulation- interesting food and music are readily available. Or visit the zoo- plenty of sounds, smells and sights there. Or get a massage, or go swimming or take up yoga or do whatever you think you'd enjoy. It sounds like you need to push yourself to enjoy your life a bit more.