What Are The Side Effects Of Emergency Contraceptive Pills?

Good morning. I am on my 15th pill (althea) when suddenly I had this pinkish brown discharge. I was alarmed because for the past 3 years, I never had spotting like that. I forgot my 14th pill but I immediately took it in the morning the next day. My husband and I had sex on the 12th pill. Could I be pregnant? What are the chances that I am pregnant? Or it's just the side effect of pill?