is it pregnancy or period?

I have been diagnosed with pcos. Came off birth control and husband and I began trying. Three months after not taking bc we started really thinking about trying. So now, I am about a week and a half before my period should start. Today I have had light cramping, lower back pain, also very light, and a bit of brown bleeding. It is off and on and isn't not heavy or hurting badlt at all. Seems like the first day or so before a period kind of. Now, could this be implanting of the egg or just pcos starting to be ugly again? For three months I have had a regular cycle. Why would it begin to act up now? But this is all reminisant of pcos problems. What does anyone think? Any similar stories or advice for me. I know going to the dr is one but I am looking to see if others are having issues or if its normal. :-(