Thank you for your reply,
Please read
this link, here it says that I can have both permits at the same time. I also called IRCC, under work permit category there is an option about getting study permit when you have a work permit and there she says you can work until your work permit is not expired. So I considered that my work permit is valid.
Anyway, after getting my permit I have registered in the university and reduced my working hours to 20hr a week. My work is outside the university and in skill type A. Can I use work experience during my education for my PR?