im so sorry to hear that you didnt have a pleasent experience at your ultrasound

i have no idea why you couldnt see the screen.... like hello of course you want to see, its YOUR baby! everytime ive had a scan, theres been a seperate screen for me to watch. and i would have thought the sonographer would have spoken to you 'heres the head, heres the feet' hmm not sure about that one.
as for the NT results, they give you a combined risk factor scan & blood test. my blood test came back with a risk factor average of a 36yo woman (im 24) but the midwives at the birth centre reassured me that it wasnt classed as 'high risk' but 'higher than average'
they an refer you to a genetic counsellor.. so look into that if you feel you need to discuss it anymore.