Super worried and confused

I'm supposed to be 6 weeks today with my 3rd baby. (4th pregnancy) Saturday I had some light brown spotting which had me worried. That's exactly how my miscarriage started in 2016. Yesterday I had A LOT of dark red bleeding and even had clots. I called my OB and they had me get bloodwork done today to see where my levels are. If they're at a normal level, they'll have me come in for an ultrasound. If not, it's likely a miscarriage. I took a pregnancy test to see if the line was getting faint and it's actually darker than the control line now. I'm trying not to stress out while waiting for a call back about my blood work. Has anyone had this before and not had a miscarriage? Thanks in advance!