Why Did I Miss Periods For 2 Months And Now Have Only A Very Light Period After Taking An I-pill And Then Regestrone?

Hi, had unprotected sex on 4th jan an had taken ipill within 24 hours. Post that got a regular period on 22nd January. However, missed periods for 2 months and as advised by a doctor took registrone for 5 days. Today got my period but it is very light as compared to normal cycle. Is there anything to worry? Is it the side effect of ipill or am I pregnant