Nausea after Nitrous Oxide was stopped

Went to the dentist today for a root canal.. Had Nitrous Oxide prior on oral surgery (wisdom tooth removal) with no ill effects afterwards but this time around I suspect either it played a role or was just a coincidence. Basically after the nitrous oxide was stopped and oxygen was given I got up and immediately felt weak in the bones and felt nausea. I'm not sure its cause of maybe a lack of blood flow to the brain from being laying flat in the chair or possibly related to low blood sugar since I am type 1 diabetic. At the time I didn't think about checking my blood sugar but they did notice my blood pressure was a bit low. Kind of stumped cause from what I was told and read there is no after effects of nitrous oxide once it has been stopped and oxygen has been given.

Too much nitrous oxide does cause nausea and vomiting. So if it wasn't due to low blood sugar maybe they gave you too much this time?

Not sure if I did get too much.. Then again if I received too much and received 100% oxygen after the procedure the nitrous oxide should have been out of my system from what I read.

I'm not a dentist just a nurse but, you may have experienced what's called Postural Hypotension, nitrous oxide will lower blood pressure a bit because you are relaxed. After lying flat for a while and standing up you had a quick further drop in blood pressure that makes you feel weak, dizzy, nauseous and can even make you pass out. You maybe could have used a bit more oxygen, gradually sitting up, dangling your feet at the side of the chair before attempting to stand. Wouldn't hurt to eat a complex carb before either if you're taking your normal dose of insulin and have a prolonged procedure.