Missed period..now spotting!? HELP PLEASE!?

So, last month I missed my period. I started to get it, very lightly for a little while then it stopped and never started. I'm on the pill, have been for a few months. I figured I was really stressed with school, and decided to wait until my next period. If it didnt come, I'd take a Pregnancy test. I'm only in the middle of my next pack and I have had light to mild bleeding on and off rove five days with cramps, etc. I still have over a week until my placebos start. Whys this, my period trying to start, preg. symptom? SUGGESTIONS?