Will this be too much Adderall?

So I took a 20mg pill of Adderall last night around 10 or 11. (Not sure if it was fast acting or slow release.) I took it so I could stay up and do all of my homework that was do today. It's now 6am and I think it's starting to ware off because I'm feeling kinda tired. Would taking another Adderall to keep me awake be a bad idea? How much risk is there? I am female 5'8 and 150lbs