I had the Nexplanon implant for almost two years up until April 2013.
My experience with it was definitely mixed.
I had a continuous period for around seven months which fluctuated between light spotting and extremely painful, tight, very heavy periods for around four months. It was unbearable. But because it is rated as the BEST form of contraception, not just for its reliability, but because you don't have to remember to take it everyday, which is FABULOUS. That's probably the only thing I miss now.
For the first year I was in agony whenever my period arrived, I had embarrassing mood swings, I was violent, snappy and extremely hormonal. I found I was very depressed for a short amount of time when it was first inserted and always found I was very tired. In the end I gave up participating in my cross country team because I was that tired all the time, which is heartbreaking to think about now... but hey, what's done is done!
I had very bad headaches whenever I would go to go to sleep and found I was more of an active thinker, strangely enough, these persisted at work and throughout my exams and even made me pass out in my first January A2 exam this year which was catastrophic.
In the end I ended up taking Gedarel 30, a combined contraceptive pill, along with the Nexplanon to try and re-arrange and regulate my periods which was a definite plus. I found my periods to be more regular, shorter and much less painful which meant my Nexplanon experience was a heck of a lot nicer than before.
I ended up removing the Nexplanon as I decided it was causing too much hormonal damage to me, and both my partner of 3 years. Yup, we were 15 when we got together! Hahah. It was a nightmare!
DON'T TAKE MY EXPERIENCE AS ANY DISCOURAGEMENT.
My friend has had the Nexplanon for two years now and thinks it is absolutely brilliant. She is the lucky 1/5 of girls who have the Nexplanon that experience no bleeding, she has had never told me of any serious or agitating side effects, other than more spot breakouts across her shoulders and her forehead and that she is slightly more irritable on the odd occasion. But other than that she adores it! It effects each women completely different. And I'm really hoping you get a positive one!