abnormal uterine bleeding
"I'm 18 and I started the depo shot on March 1, 2016. The shot was wonderful all the way up to May. What they say is true. The first two months were great, but now I've been heavily bleeding for 2 1/2 weeks. Because I suffer from migraines, I can't take "normal" birth control. The progestin ones only. So I was only offered 3 options: the depo shot, pills that caused me to have 3 periods in one month, or a foreign object in my arm. I'm totally done with birth control which  sucks. I want to have a baby sometime in my life, so I don't want the decisions I make now to affect my fertility in the upcoming years. 

I would NOT recommend the depo shot. The negatives HEAVILY outweigh the goods."