Doppler

I really want to get one as I'm struggling every day with not knowing what's going on in there. Every day I'm not sick I'm worried, heck, even when I am sick I'm still worried something's wrong in there. But I'm also so scared of not being able to find the heartbeat and freaking myself out. Ugh, do you ladies have one? Do you recommend one and how many weeks were you when you found your babies heart beat? Was it hard to limit yourself to use? (I can see myself wanting to use it every second of every day)