It's silly, but I'm nervous

I have a appointment to see my doctor this afternoon and I must admit, I'm a bit nervous. This will be the first time I will get to hear my third child's heartbeat. My last appointment was just a little too early to be checking for it. I'm really glad she didn't even try because if she wouldn't have found it I would have just freaked out until this appointment today.
I really am not all that sure why I am so nervous, but every time I think about it I get butterflies in my stomach. First of all, I just really want it to be there for me to hear. Someone I care about very much just lost her baby and she was a couple weeks farther along than me. That scared me more than I admitted to anyone. Once you get past a certain point you tend to let your guard down a little, or at least I do. I realize anything can happen at any time. So I really just want to hear that little thump-thump-thump.
The other thing I really want is to just hear one little heartbeat. For some reason I am terrified of having twins. I know the odds are low, but I am still worried. I even dream about it. I am getting bigger faster this time so everyone says "oh, maybe it's two" and I smile and laugh while inside I am screaming and crying. What would I do with two? I don't even want to imagine the possibility.
So, I will update later and let you all know what I hear. Good luck to us!!