Brown discharge, No period, negative test

Lu
Okay ladies. I'm on cycle day 45 and have no symptoms, and no period. I've had to push back my start date on glow 3 times already. I miscarried in May this year and I've had 28 day cycles ever since, until this month. On the 5th this month I started having brown discharge (28 days after last day of last period) but no blood. This continued on and off up until about 5 days ago. I took a pregnancy test last Sunday and it was negative. The last time I found I was pregnant I was 3 weeks along with horribly sore breasts and crazy mood swings, but I don't have any of that currently. What else may be causing this, should I test again? Thank you in advance!