Doctor had hard time finding heartbeat. Anyone?

I'm 14 weeks and when I went in Monday for my checkup they doctor had to really search for babies heartbeat. She finally found it, but it wasn't as clear as it has been and she had to really press down on my tummy which was painful to get it. Now I'm just paranoid.. I've miscarried in the past & almost last my second child due to cervical shortening. Oh and I also used to feel flutters and they have stopped. Anyone else experience this and baby be fine? This is my 4th pregnancy.