birth control
"I had Implanon implanted two years ago. The first month I had my period for over 18 days. I experienced such changes with my hormone levels that I would cry, or be outraged one minute from the next and I couldn't control the way I felt. I'm a completely rational person and whatever hormones are in this literally made me want to cut it from my arm. 
After the first three months, of which I had four days each of the rage/crying/uncontrollable emotions, everything seemed to level out. I haven't had my period for a year and a half now. If you make it through the first three months, it's great. "