6 weeks is sometimes too early to see a heart beat. But the bleeding and clots are not a good sign, though there are people who have bleed and are still PG, maybe having lost a twin? I had a bleed before I knew I was PG, thought it was just my AF, never had m/s, but sore BB went before M/C.
I hope that all is ok though, and that the Ob has some good news for you.