Ok so my cycles are usually 32-35 days long. I have been ttc for 2 months now and ever since then, my periods have been all out of whack. Last month came a few days late, then it was brown and very light. Lasted about 6 days. This month I was 6 days late and started off brown and light again. It only lasted for about 3 days and stopped. But when i went to the bathroom i noticed a stringy blob of cm. I had cramps for about a week and a half that led up to the brown spotting. Still get cramps after the 3 days is over. I have only had one partner so it's not an STD. Took a pregnancy test on day 2 of spotting and negative. Any idea what's goin on?