Doppler

So my friend leant me her foetal Doppler, I am 10weeks 1 day and have now worried myself because I can't find the heartbeat even though I know it's sooo early to be able to, also I'm overweight so don't know if that makes it harder. I'm in the UK and still have to wait another 2 and a half weeks for a scan. I just want to know my little plum is ok!!! Feeling frustrated and worried now!! 😣 x