Depo downer

So in 2014 I started taking the depo shot and immediately stopped having cycles. A year after I decided to take a break from it. I was off for 8months before I had a cycle again. 2 weeks ago I decided to start back getting the shot. Now new rules are you have to pick up the prescription from your local pharmacy blah blah when you start your cycle come in and get  the shot. Well I got the shot and I've been spotting ever since. IS THAT NORMAL?  It didn't happen the first time. I'm ready for it to end LOL I had it made the first time; No cycles, went from 5'5 115/120 lbs to 5'5 148lbs. No acne. Hair was still healthy as ever. So why is it different this time?