My stomach always hurts after i drink coffee?

help. my stomach ALWAYS EVERYTIME ******* hurts when i drink tim horton's coffee. i usually get a triple triple. and some baked goods. but after i drink the coffee, and 10 min later, my stomach ALWAYS hurts like i have to diareha or something. anyone know why that could be??? and i loooove coffee so i do want to keep drinking it........ thanks. o and im also 18, female.