Brown spotting but theres a baby and heartbeat

So ive been having brown spotting/bleeding since I was 4wks.

Im now 6w3d. Yesterday I had an early scan and to my surprise the baby is there with a heartbeat!

The doctor found no reason for my random bleeding. I’m still super scared and worried about it... i cant get in my head that this is normal...

Anybody had brown spotting/bleeding and was fine later on?