Pregnancy after implanon removal?

I was using the Implanon contraceptive implant for 5 years in total. I had it removed last month and have been trying for a baby ever since. I have missed my period recently, which I just assumed was related to the removal of the implanon.

But I have not had any signs of any period coming on, so I have done some pregnancy tests but they showed up negative. Could I still be pregnant or does it take some time for these kinds of birth control implants to wear off?