Flying (airplane) problem?

Hi everyone. I'm very concerned about airplanes. Something like this has never happened to me before, but this is the first time I've experienced it. Symptoms: collapse while conscious, a pounding in my head, profuse sweating, and the feeling of vomiting. It happened on the plane. Not immediately after takeoff, but after 1 hour and 10 minutes. Apart from nausea, the other symptoms disappeared after 20 minutes, and by the evening, everything was fine again. Is this a fainting spell? I'm flying to Mongolia in January and I'm worried it might happen again. I'm not sure if it was a fainting spell…