Andominal pelvic ultrasound. Please help

Could anyone please tell me if doctors can tell if your pregnant by looking at an abdominal pelvic ultrasound?

I had an ultrasound done 2 1/2 weeks after I had sex because I had pelvic pain and pressure, I then had another scan 6 1/2 weeks after sex because I still had strange symptoms.

I took a test and it was negative , but being so early and having an ABDOMINAL US (I know you can see pregnancy early on vaginally) ... If I was to have been pregnant would they have seen early signs of pregnancy and noted it on my report or told me they would need to do a vaginal ultrasound to have a better look?

I didn't ask them about pregnancy because at the time I wasn't concerned about it , I thought I may have had a cyst but everything on my report was clear, that's what made me worry about pregnancy and perhaps they just didn't include it in the report...

Even if they didn't see a baby, would they have seen a sac or something like that? I honestly have no idea about this stuff.. So any advise would be appreciated.

Any pictures would also be great... I am not wanting to be pregnant, I'm just concerned that pregnancy could have been missed because I'm not sure how this all works.