What Are The Side Effects Of Using Emergency Contraceptive Pills?

This is tanu. Am 21 years old. I delivered my first baby 6months back. I started taking contraceptive pill(cerazette) for t past 2 and half months. After delivery I didn't get my menstruation properly. For the past 3 days I am feeling dizziness, having vomiting sensation. Am worried if am pregnant. My child is just 6 months. I didn't take pregnancy test. Am worried.