Where can i go to hear my babys heartbeat besides the doctors ?

So i am 11 weeks i guesss… and i dont feel pregnant at all my doctor keeps rescheduling my appointments idk why… and i havent even heard my baby heartbeat or seen the fetus yet through a ultrasound.. im panicking and worried that if i still am pregnant because i feel like im not . Supposedly i am because the test was positive…. Im getting stressed and anxious if I really am though the doctors fault for keep rescheduling me … what do i do? Im stresseddddd if i even am or what… i feel NO SYMPTOMS….