Light brown discharge and lower abdomen pain

Hey all!! Im around 5-6 weeks pregnant and for the past 3 days I’ve been like “spotting” the first day it was light pink for a few hours then it got brown and i could only see it on tissue it never spotted in underwear now for the past 2 days it’s off and on very light brown discharge that I also only see on tissue but it’s accompanied with light cramping in the lower abdomen and lower back

I have a ultrasound tomorrow and I’m sooooo nervous 😩 they seen a sack Monday with no baby but that was progress from my last one before that they seen nothing has anyone gone through this ??? Healthy pregnancy??