skyla?? is it "working"?

Julia
So I used to take the pill but I was so emotional and got pimples all the time that I stopped taking the pill and got the Skyla. The insertion wasn't painful and I only took an Advil right before the appointment just because the nurse recommended it. 
It's been two months and I got my first period but it was a light period and I've been spotting for 4 days past the day my period should have ended.
Other than that, I have no cramps, no pimples, no weight gain, no emotional roller coasters, no nothing. I've read a lot of posts that people have the worst side effects with Skyla. Should I  be worried that I got a defect Skyla or it's not "working"? Or am I just lucky?