Hi, I have been on nexplanon for about 9 months now and I think that it has made me gain about 15-20 pounds on it as I was around 165 lbs when I got it and I am now 183 lbs. I was worried that it might not be as effective because of my weight? I am 5 foot 4.5 inches. I have just started to worry about this since I have not gotten a period in a few months (period has been irregular since going on this) and the tips of my nipples have been sore the past few days.