What Causes Sudden Syncope?
Looks like a syncope
Detailed Answer:
I read your question carefully and I understand your concern.
Judging by the circumstances of the episode, in the setting of prolonged standing I presume and hot environment I believe it to be a syncope, more specifically a vasovagal syncope. A syncope happens when there is low blood pressure with insufficient blood supply to the brain and hence alteration of consciousness at times, when prolonged may present seizures and can be accompanied by digestive symptoms like vomiting and afterwards dizziness and confusion. Vasovagal means due to the mechanisms which regulated heart rate and blood pressure in different circumstances not working properly temporally.
It is often related to a trigger such as strong emotions or the heat and standing as in your case. Usually it is a benign phenomenon and you should gradually be back to normal.
Tests which might have been done would have been a blood panel for blood glucose, electrolyte changes and an EKG, however since in your case there is a trigger and it’s been some time I do not think it’s of much use now. If it repeats at least EKG is recommended to look for abnormalities of heart rhythm. Also the new medication should be evaluated, you do not mention its name, if it’s something which affects heart rate and blood pressure might have been a factor.
I remain at your disposal for further questions.