My last proper period was on the 16th of may which lasted 7 day as usual, my next period was then due on the 17th of June but didn't end up coming til the 28th and only last 4 days unusual and it wasn't like a normal period either I had a little brown discharge then semi heavy 2 days then spotting for the last day or 2 and now 8 days after that I have dark ish brown discharge, the day before this "period" happened I had extremely serve pains in my stomach to the point I could hardly move. At one point I did think I might have been pregnant but I did a pregnancy test the day of my expected period (17th june) and it was negative. Any suggestions on what's going on?