I Am 17 Years Old.. My Boyfriend And I Are

I am 17 years old.. my boyfriend and i are sexually active and we use the withdrawl method.. but now my period is 3 days late, ive had creamy, milky white discharge in my underwear one day. When i wake up in the mornings my stomach hurts bad.. i sleep and urinate more often. I never threw up though. Is there a chance i could be pregnant? Should i wait a couple more days to take a test since my period is only 3 days late?