Last Night I Ate Six Cookies From McDonald's - 3

Last night I ate six cookies from McDonald's - 3 chocolate chip cookies and 3 oatmeal cookies - I have been diagnosed at pre-diabetic, but when I took my blood glucose level after 2 hours of eating the cookies, my reading was 211 - I know that this high, but it did go down to 159 and lower within 1/2 hour of checking after some exercise. Should I be on medication for diabetes?