First time with nexplanon

Hey guyssss so I recently got the implant(nexplanon) I got it almost a week before my period was due to come(I got the implant on Jan 2, period was due Jan 7). The day of my period comes and I did not get it. (I am also on the pill). Now it’s been 20 days and I still haven’t gotten a period. I took a digital test last night,it was negative. Should i be worried that I could be pregnant ? I’ve been getting these awful cramps since I had the insertion done.