Sayang, any bleeding during pregnancy especially at 30 weeks memang kena ambik serius, please follow up with your doctor or go to hospital immediately if ada more bleeding, even sikit ja. Your doctor already checked and said it's not from the womb which is good, but only a proper scan and tests can identify exactly where it's coming from (bisa je dari saluran kencing or other areas). A few of my mum friends had unexpected bleeding during pregnancy juga, so you're not alone, tapi each case is different, jangan stress sangat, just monitor closely dan report any changes to your doctor, ok? Ini bukan something to figure out sendiri, amat need professional follow-up for your and baby's safety. Hang in there!