About 4-5 weeks! -normal?

Is this normal at 4 weeks? My first pregnancy I was 5 months when I lost him due to complications but I spotted lightly at 8-9 weeks. My second I was 5 weeks when I lost it and I never spotted. I’m now about 4-5 weeks and just started this.. I have an appt tomorrow because my doc is extra extra cautious with me after everything and he is gonna do an ultrasound to make sure there is at least a sac there. Which is how he knew I had a miscarriage the last time, with an ultrasound at 5 weeks. But could this just be implantation bleeding??