HiAnon912 and thanks for your question.
If he pulled out before he came then you would not be at risk for pregnancy.
Are you saying you took an emergency contraceptive pill (ecp) when you say you took a "pill" or are you talking about a regular birth control pill? The effectiveness of an emergency contraceptive is stronger when they are taken within 24 hours of unprotected intercourse. Side effects can include changes in the timing of your period, an irregular period, and more. The manufacturer of the pill you took should have information online which can help you better understand the possible side effects.
There is information online claiming that large doses of Vitamin C can induce a period and/or cause an abortion. Taking large doses of any substance, including vitamins, is not good for your health.
Hope that helps,