Touring is one of the most elective activities that I know. The only reason to do a bicycle tour is personal enjoyment and satisfaction. When a tour becomes a daily grind that you dread it's time to make changes. Of course I would apply criteria like they do for clinical depression, in that the feeling is persistent, and not just a mood swing. I'd try and stay put for a while and work hard at learning new things about the new world you are inhabiting. I think it's hard to let go of your previous experiences that have been glorified and edited in your mind. Try to avoid comparing the past and focus on the now.
From Thich Nhat Hanh:
Do not lose yourself in dispersion and in your surroundings. Practice mindful breathing to come back to what is happening in the present moment. Be in touch with what is wondrous, refreshing, and healing both inside and around you. Plant seeds of joy, peace, and understanding in yourself in order to facilitate the work of transformation in the depths of your consciousness.