Strange Period...

Hello! I'm new here and just getting used to these forum, so forgive me if this is posted in the wrong place.
Anyhow, I need some help so i'll give you a little background first.
I started my period when I was 11, ever since I was 13 it's been regular (i have sorta long cycles though). I am 20 now. I was on the pill for about 2 and half years. I quit about 4-5 months ago. Since quitting, i've still been regular. Except for this month. I had my period for 2 days (they usually last 5). The first day was heavy, the second day was really light. That was two weeks ago. A couple days ago I had a very small amount of brown spotting. Today I had a very small amount of black. I don't have any pain or anything, so I have no clue what's going on. I'm hoping that my body is just adjusting from being off the pill. Anyone know what's going on with me? I'm a bit freaked out. Any advice would really be appreciated. Thanks so much, and sorry for the rambling!