What Causes Feeling Of Lightheadedness And Excessive Sweating?

I am a 22 yr old female, and I don't have any major health issues that I'm aware of, but.. a few minutes ago, I was taking the elevator up to my floor and I began to get quite light-headed and I started sweating. It was all I could do to make it all the way up without falling over. When I got to my hallway, I sat on the floor and took off my jacket and hoodie. I was sweating all over by this point. Then I started to get nauseous and I threw up a couple of times. After that, I felt immediately better and was able to get up and walk away. There was no chest pain, but I did take my anti-depressant this morning and I'm not sure if I should take it again.