need reassurance- plan b & periods

So I’m just asking as a young woman who needs some reassurance. I had sex on July 19th, a condom was used, but I was unnecessarily concerned so I took a plan b pill. had sex twice after then on different dates later on, and then my period started really early, on the 25th. I figured it was just because of the pill, but it was odd because it only lasted about four days and the flow was so light that it could’ve been mistakes for spotting. It is now August 6th, and my period has just started again, once again, unnaturally lighter than usual. Is this normal for it to be so light and keep starting so early? Could use some opinions.