Ultrasound help?

Can anyone tell me what this is?

I had a private scan at exactly 6weeks. The tech scanned for 5 minutes max, immediately saw the one baby and checked for heartbeat(128bpm) and said baby looked good. I saw a second black blob on the screen and the tech kind of shrugged it off and said it was probably a cyst or something and didn’t check it at all.

Does it look like a second sac?? Or what could it be? I have a diagnostic ultrasound on Friday so I think they’ll tell me for sure. I just want to be prepared just in case!!

Thank you!