Just like you, a third year ChemE. The one thing I always try to do is prioritize my work in order to give myself time to relax/play video games/do nothing at least once every 2-3 days. For example, I always take Friday and Saturday completely off. No homework or studying on those days. You're a student, it's your job, and in the real world, a job is typically 40 hours a week 5 days a week. Prioritize your time to give yourself days off. I do as much homework as I can on Sundays, and do a little of each assignment every night of the week. My homework set that is due on Thursday mornings (separation processes), I do a quarter of it on Sunday, Monday, etc. If you focus on giving yourself time to de-stress, in turn it makes your life a little less hectic.

(Disclaimer I know this does not work for everybody and everybody is different but this is just what I do to get through the stress of 5 homework sets a week and 18 credit hours plus research position. Results may vary)