Spotting during pregnancy ??

I have spotted 3 different times in my pregnancy, at around 3 weeks when I first found out, at around 5 weeks, and today at 7 weeks 3 days. I have told my doctor and she said as long as its not bright red and I’m not having cramping to not worry about it. The spotting is brown and goes away after a couple of wipes. I’m just really concerned. I haven’t had my ultrasound to confirm heartbeat yet (having that on Tuesday.) and I am just really worried. I pray to God every night for a healthy pregnancy. Has anyone else gone through something similar? Can anyone please reassure me .