Brown discharge at 6 weeks

Hi, I had conceived through IVF and had an ultrasound the past Tuesday and saw the embryo's heartbeat. I'm somewhere at week 5 going on week 6. What has been concerning was that I've been having brown discharge almost daily, sometimes when I do big business, and sometimes a trickle spotted on my panty liner. I've read up on this, and it seems like if it doesn't turn red, it's still normal. I don't have cramps either. But this morning, the amount I saw on my liner was of a larger amount than usual and that startled me. I'm afraid if this is an early sign of miscarriage... I'm going to try and get an earlier appointment to go in for ultrasound again, but in the meantime, can't help overthinking. Has anyone had similar experience before? #advicepls #firsttimemom