11 Weeks Pregnant

So i had a scan at 9 weeks and everything was perfect our little baby was waving and moving like crazy which was a complete relief as i suffered a miscarriage late last year and i was experiencing brown discharge after sex but everything was fine

I am now 11 weeks with my 12 week scan next week but i don't feel pregnant anymore, i am still tired with sore boobs but i don't even have a bump yet.

I am just praying everything is perfect again. Our doctor suggested to purchase a heart fetal doppler to put our minds at rest which we can clear perfectly but there is always that doubt in the back of my mind.

What is the miscarriage rate after seeing a very strong heartbeat at 9 weeks?

Thank you,

Leanne