alternatives for adderall?

i need to be revising for my exams but i find it so hard to focus and have such a short attention span. i literally have an exam in a few days but i'm so behind because i cant sit down and focus for even a few minutes! im pretty sure i have adhd. anyway after searching about it alot of people said to get adderall but that's not really an option. so wondering if anyone has any alternatives that will help me focus, doesnt have to be drugs just anything at all! thanks