Is Modafinil Safe To Improve Concentration And Alertness?

hi i am a student in my final year of college. i have just over a month left for my exams and i am getting worried. i feel like i am tired alot of the time and anbale to concentrate to the best of my ability, i fear i will not be able to get the quality and amount of revision needed to get my grades. i was looking on the internet for something that may help me and came accross modafinil. i read that it is a wakefullness promoting durg that increases your concentration and alertness. do you think it is right for me? if so, do you think i could get an NHS/private prescription?
Thank you