is it to early could the scan be wrong

Lucia
My first scan has revealed this I should be 8 weeks if I go by period but I have pcos so bbt chart if it's correct denonstrates I'm 5.6 so 7.5 weeks teqnically she
 said she could be wrong but she's 50/50 % sure iv had a loss I go back next week to check again has anyone experienced this? 
She said she can't even see a yok sac or a baby
Iv had no loss symptoms, but because she said she's 50% sure she could still be wrong right? I'm so upset and confused Please help