Tilted Uterus

Has anyone else had issues finding the baby's heartbeat on a Doppler? I went to my doctor's appointment today (11w2d) and they had trouble finding the heartbeat, but he said it's nothing to be concerned about because my uterus is tilted backwards. I have to come back in 2 weeks to recheck, and hopefully they can find it then. Is anyone else having this issue or have had this issue? When were you able to hear the heartbeat on the Doppler?

(we had an ultrasound last week, the 19th, and everything looked good, and we even saw the little heart going, so I'm not terribly concerned, but I am of course, as a mother, concerned.)