pregnant, birth control, sos

hey ladies. so 1 month ago me and my boyfriend has sex everyday for like 3 days. all times were protected, but scared of the thought of mistake, we took plan b in between, i got on the nexplanon implant that week and it doesn’t work for 7 days. i got my period 5 days late and it lasted 7-8 days. i thought it was my period bcc of the cramps, but it was lighter. 5 days later i have started to bleed a little again. my boobs are sore. ladies what are my chances of being pregnant? should i worry? is this common? please help