Very nervous

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So I'm about 6 weeks 5 days and today I noticed for the first time a drop of brown blood in my underwear and I've had some brown discharge when I wipe. I've noticed lots of other women post about it but I've passed them up because I wasn't experiencing it. Unfortunately the Internet is driving my mad. I haven't had intercouse as I've been too nervous so besides something terrible i don't know why else I would be having this brown discharge. A lot of sites are saying it's probably okay but that it could mean a missed miscarriage or the start of a miscarriage. Has anyone had brown discharge not related to intercouse and their pregnancy turned out okay? All the sites say to call the doctor but I do have an ultrasound scheduled for Monday. I'm just really freaking out. This is my first pregnancy. Thanks in advance.