I am 3 weeks pregnant. previously lost all three pregnancies. should i go to the doctors straight away or wait a little? what could they do to help?

Recurrent loss: losing 1 pregnancy can be by chance, however the lost of 3 pregnancies in a row gives you a diagnosis of recurrent pregnancy loss which might be helped by a doctor's evaluation. ideally this occurs before the pregnancy so that any anatomical problems can be ruled out. would not hurt to see a doctor early and get your labs checked.