Went to Ikea with my SO to search for a new bed for the apartment. While there, my body started feeling really exhausted, I started to sweat, my legs wanted to start giving out, everything got white (I couldn't see), and I couldn't hear out of my ears. As soon as I sat down my ears started ringing, then it just went away and I felt a little better. Has anyone else experienced that? What could it be and why does it happen? It scared me as I've never experienced anything like that in my life.