Is it ok to take ADD meds then stop taking them for a while then start again?

I have a medical problem (that I am still having test run to see what is it.) My mom told the doctor that i forget things a lot at school. Like books,my purse ect. So he put me on ADD meds. I took them for a couple days then stopped completely. My mom got mad and said I can’t stop taking them but wouldn’t tell me why. My question is why did she say I can’t stop taking them? I didn’t see any difference in when I took them and when I didn’t. Can me not taking them for about a week then suddenly starting again (my mom made me) can that effect anything? Thanks.