I tell myself, " there is always someone in the world , that has worse problems than me". That helps me to think positive.

Maybe it's not a nice expression, but whenever I hestate whether to study for at least a couple of minutes or go to sleep (or do something unproductive), I call myself a lazy prick and also think that If I want to achieve something in my life, I have to invest myself in it. According to the rule that nothing comes without an effort:) Good luck with motivating yourself:)

Bad day or bad years?! O_o

Just be strong.

It depens, I usually would just make myself busy and know that there will always be tomorrow if I don't give up. I always fight against bad days :D I hope you do too!

If you mean bad days in reference to while you are learning a language do something that doesn't feel like learning. For example, listen to songs or watch movies in the foreign language you are trying to learn. Good luck!