Hi and thanks for sharing your question with us on HCM. Becoming sexually active can bring changes to one s period cycles. It sometimes might make the period come sooner. The light pink spotting could be the onset of your period. Even though you had protected sex, it is never 100% guaranteed that one will not fall pregnant. Upon conception, some women experience an implantation bleed when the zygote (fertilized egg) implants itself into the lining of the uterus. This is a light bleed that lasts for 2-3 days. Then again, this does not necessarily mean that you have fallen pregnant. My advice is to give it a few days. You may just have a regular period. If you are still very worried, you can consider testing with a home pregnancy kit to test for pregnancy but they are not very accurate. The most accurate method to determine if you are pregnant or not is to perform a blood test for serum Beta-HCG. This can be done with your regular doctor. You do not need to fast to take this test. I hope this advice helps. Good luck and take care. Dr Shabnam