What is the little white round pill with 5 on it?

Might be

Drug Name: Methylin

NDC: 00406-1121-10

Ingredients: Methylphenidate Hydrochloride (5 MG )

Color: White

Imprint: 5; M

Shape: Circle

Form: Tablet

aka generic for Ritalin®

Next time you need to find out what pill your holding go to drugs.com then pill identifier