Feeling tired, can't focus, feel unmotivated, but have to study for a Master Degree admission exam.

Given that I work Monday to Friday from 8 AM to 6 PM and spend additional 3-4 hours in transportation, I need to be efficient with my free time on nights and weekend. Currently, I feel unable to do so.

I have read about Nootropics. Are they good? Have you personally tried them? Are their benefits worth the secondary effects? Which one do you recommend that you can buy easily without a prescription?