Positive pregnancy .. but bleeding.. Is it miscarriage ?


I m 6 week pregnant.. but suddenly yesterday i started bleeding and is continued..so i went to doctor.. doctor took an ultrasound and said everything is okay but cant say why bleeding happened.. so gave blood work and waiting for reports.. i m worried that it is a miscarriage.. I don’t have any pain.. what are the symptoms for miscarriage?

did anyone face something like this?