Bleeding with blood clots

Hello! I tested positive after missing my period for a few days, initially its was just some spotting but as the days go my bleeding became more heavier and even have chunks of blood clots, I'm almost 5week pregnant I have check up with a gynae but my sac was not able to be seen over the ultrasound, Doctor say It might be due to too the fact that's it's too early to been seen or I might have miscarry it. Any mummy out there have experience the excessive bleeding with blood clots? Please advice ☹️