I've been on nexplanon birth control since August of 2013. So this August would be 3 years - the limit of nexplanon. Ever since I got it put in, I've been getting my period more than once a month - probably twice a month, having a week long period span. The last period I had was on my birthday March 21. Lasting about a week. I was reading about nexplanon how it loses effectiveness as the years go on. After the second year, it only releases about 50% of the hormones, which makes sense because it's about to stop working at 3 years. I've taken two pregnancy tests, one being at the doctor and both were negative. It's the middle of May and I haven't gotten my period still, but am having spotting after sex. Could I be pregnant? Why haven't I gotten my period in so long? Help!