Drs said ... ultrasound/ectopic

So I had a ultrasound today they couldn’t see anything at 4 weeks and 4 days they did say however that they could see a area on my left area ovary that could be a corpus lutem or a cyst .

They took bloods which are fine for early pregnancy and I have to go for another ultrasound and bloods in 48 hours to rule out ectopic !

Can anyone shed there experience or some light on this and by now should I be bleeding or anything if it was etopic ?!