What Cause Two Menstruations In December, Followed By Missed Period And Light Brown Discharge?

Am 24 years of age. My periods havr been irregular ever since. Tow months ago, I received my periods twice in a month.( that is after 14 days). That happened in December. In January I was expecting my periods towards the end of the month but till now am still yer to receive. From then I have had extremely delayed periods. What I have been seeing in a couple if days now is a light brown discharge from my vagina. Please help me