With your students, be strict, but be gentle. Be loving.
Same with yourself:
Be strict, but be gentle.
If we were not disciplined at all, soon we would end up living in the street, with months-long beard, fat and laying on the ground.
So be disciplined.
Take care of yourself, do your work, practice some sports, eat properly.
But at the same time also be loving.
Don´t demand to much from yourself.
Be to yourself the way that you want to be to others.
If a friend comes to you saying he can´t do something, you are probably not going to say that he is stupid and that he should be able to do it. More probably you would say that we all have our times, our process, and that he should be gentle with himself and learn at his own pace, step by step.
Be to yourself like that.
Speak to yourself in that loving and understanding way.