Drs said i had a miscarriage can they mistake it ?

Probably not: If you had a proven pregnancy and saw products of conception in a heavy period, then you probably had a miscarriage. If your serum beta-hcg confirmed pregnancy and then the number dropped, then you probably had a miscarriage. If you just had signs of pregnancy (breast enlargement, weight gain, morning sickness), but then just a very heavy period; then it could have been a prenancy and miscarriage.

Depends: If your doctor saw fetal heart tones one time and then did not with the follow-up ultrasound, then you have, unfortunately, miscarried. Where a mistake can be made is if nothing is being seen in the uterus and your pregnancy levels are not rising properly, then you could have an ectopic pregnancy. If your levels are rising but nothing seen in the cavity, you may have more than one fetus developing.