At this early stage the ultrasounds are really quite accurate, more so then further down the preg track. Generally they give a week leeway either side of the date the scan has given them, but I believe that is in later scans (ie 13 or 19 week scans). The fact that the yolk sac was still visible it is unlikely that you're 10 weeks, it's usually gone by then.
The bleed doesn't make much sence to me, but I'd say you can be confident the u/s is pretty well on the mark, but I'm no doctor!
Sounds like bub is nice and healthy, hope you're feeling well. Hope you get some solid answers soon!