Relieved and also Nervous!

Good afternoon ladies! 
I had my first OB appointment today and so far so good! According to my LMP I should be 8 weeks today... But thinking we ovulated later in my cycle I am measuring at 6 wks 5 days.. They moved my due date back to December 10th! Praying my little nugget stays put! 
We had a strong heartbeat at 123 bpm and everything looked okay.. 
But the doctor is a little concerned with some minimal spotting I have had.. And said it looks like I have a small pool of blood where the placenta is attaching.. 😬 they put me on progesterone and I have to go back in a week! Eek! 
I have still yet to have anyone draw my blood.. Is that normal?! 
If any of you have similar experience please let me know! This first time mom is freaked. 😬