Advise please as scared 😦

Had US today at 5w6d and they only saw gest sac and yolk sac, they said that is pretty normal for this time. They then said there was a mass towards my left ovary and I have to go for a follow up US in 10 days time and it is possible this could be a heterotrophic pregnancy! Went in shock (even though they told me not to worry) but now thinking I had a partial tube removal last year due to left side ectopic so could this be what they are seeing?