I’ve been spotting for 6 days; 7 weeks and 2 days

I’ve been spotting for 6 days already! (brown usually) and today it was red blood. I called my nurse and she basically said there’s not much that can be done. To basically go to the ER if I start bleeding like full blown period and having cramping. Is this obvious signs I have a miscarriage that’s about to happen? Why spot for so many days?? I was seen by my obgyn last week. She didn’t see any signs of it being ectopic pregnancy bc I was worried I might have that since a few of my friends had it and I read sometimes you won’t even have any pain. Anyways she said I didn’t have any obvious signs of having this and that my uterus already has expanded. I have an ultrasound tomorrow. This is all extremely weird and so much stress. First pregnancy. I’m worried because there’s no way this is a good sign. It’s been 6 days. I don’t spot all day but definitely every single day and today was actual like red blood. Light but it was “fresh”