Pregnancy after abortion

Patient: I had an abortion last December and about 2 weeks later I had unprotected sex. My boyfriend bought me Plan-B One Step and of course, I took it. Is it possible that the hormones my body were still releasing because of the pregnancy stopped the contraceptive from working?

Symptoms: My belly is a little bigger than usual. Other than that, I’m pretty normal except I’m dizzy in the morning and my lower back hurts, which is what happened in my first pregnancy.