What Causes Prolonged Brown Spotting While On Althea Pills For PCOS?

hi. i need help. i was diagnosed with polycystic ovarian syndrome. my first pill was yaz. but my acne keep getting more and more so i shifted with althea after a month of not taking yaz. i stopped yaz last february. i started taking althea last march 18, 2015, 1st day of my menstrual period, at around 9-11 in the evening. and the spotting lasted until march 28-29, 2015. even after that, i experienced dark red to brown scanty spotting on april 1. since i cant really sleep during the whole course when i started althea pills, i shifted taking it from evening to morning at around 9-10am. and after 2days, i slept better. april 7, 2015 was my last dose on my first pack. last april 10, i had a light to slightly dark brown spotting. i thought it just signals my new menstrual cycle. but until now, april 15, i still experience almost same color and amount of discharge, it did not even get heavy from april 10-15. why is that? please help! and btw, i started my new pack today (april 15) at 9-10am. i need a reply asap. please.