Is there any way you can feel your baby's heart beat at 19 weeks at home. my doctor is away so i cant see him?

I am just worried because it feels like my baby bump is much smaller and i spend all day worrying that my baby is not there. I cant see my doctor because he is away. my next apointment isnt for 2 weeks and it is stressing me out soooo much and am constantly worried and anxious... i just want to hear a heart beat to re asure myself that my baby is ok. is there anything you can buy on ebay etc to hear the baby's heart beat??