It is a possibility that you are having an irregular cycle, even though you have had regular ones since having the implanon removed. But it is also a possibility that you are pregnant and it is just not showing on a HPT just yet. I had this happen to me around the same time as Chody and figured it must have been a longer cycle, and I decided to wait until I missed another period and "then" have a BT. Well I missed another period and turns out I was pregnant. I will say that during that 4 weeks after the first missed one, I was a bit emotional and annoyed that my body was so messed up that I did indulge in drinks one night, as I figured if I was pregnant it would show on a HPT. Well, I was wrong, and wished I never had those drinks. I guess the emotions were pregnancy hormones lol. All I can say is, have a BT just to ease your own mind. At least you will know where you are at, as BT's are very accurate. Good Luck, and I hope you get the outcome you are after. Just remember not everyone shows on a HPT when pregnant.