Is it okay to take adderall everyday?

My brother has ADD and it does run in my family but ive never gotten tested for it, i am going into my second year in college and i have realized that i did terrible i couldnt focus or study, basically lazy! today i tried one of my brothers adderall 30mg and i felt like i accomplished so much today! i am going to the drs to see what he says.. is it bad that i took my brothers just to try it?