Early period? Need advice

Normally I have very irregular periods usually every other month. My last cycle began on February 9th, I had a positive OPK on February 23  on March 3 I began brown spotting which is still going on not anything like a period hardly there at all. Taken a pregnancy test that was negative. I'm an extremely tired and bloated but that's about it. Anyone know what this could be or have experienced this?