Lol oh God, when I was pregnant with DD my frickin' heart BOOMP-BOOMP-BOOMPing in my ear used to keep me up all night :/ I had the same symptoms as you but they went away when DD was born, so I assumed it was just a heightened blood pressure thing maybe? Although my blood pressure was really low throughout... just increased volume of blood maybe, making the noise louder somehow?

Hope all goes well