Oh I know how you feel... but...

what a great dry run!!! The nerves won't be so bad next time!

I think the best advice is to

have those easy to refer to notes
--and if nervous say that you have that written down because you wanted to be sure to give a complete (whatever) answer

breathe and take your time before answering,
even if you quickly know the answer

smile as you reply (especially since this sounds
like Skype or webex interview?) and if so...

look into the camera because that's where THEY are