Hello,

If you are able to manage by sleeping 5 and a half hours and you are not feeling lazy or asleep while studying then it's alright but i would suggest that atleast on weekends you should sleep 7 hours a day so that you will be fully charged on weekdays.

It's not important how much you sleep but what is important is how much are you focused while studying . Don't study like a robo. Whatever you will study do it efficiently so that it is kept in your head for a longer period of time.