I've had nexplanon for a little over 2 years. I was breastfeeding until October 2014. I got my first postpardum period the end of October and have had one every month since then until May. Didn't get one at all in May and it hasn't shown up at all. Is this normal? If I hadn't had this nexplanon for so long I would worry but my body should be used to the hormone by now right?