Ugh getting frustrated :(

So ive had the sonoline b fetal Doppler for a few weeks and I'm about 11 weeks almost 12 and I still can't find the heart beat :( my next Dr's appt isn't till next thurs but ughh I just wanna find it already!! Anyone else have trouble or I it just me...and the fact that my arms are short and my torso is longer doesn't help either!