From the pill to nexplanon.... PLSS HELP

So I was on the pill for 19 days , had sex on the 19th day and the 14th day of the pill and I am now on implanon, is there any way I could be pregnant? I took the pill everyday at 7 pm but I'm worried it might not have been in my system yet , I started the pill during the first day of my period too so I think I was protected but I'm just a little paranoid. And also is there any way to predict when or if you'll get your period on nexplanon ? I've had the nexplanon for 5 days.