Possibly heat exhaustion?

So on the 23rd throughout most of the day I was complaining about the heat, everywhere I went was hot, the air conditioning in my car felt hot, and I have a new car so that was weird but I felt fine other then that. But I was driving and all of a sudden I feel extremely dizzy and felt the need to throw up, it was good I was close by my boyfriends house, so I immediately lay down for about an hour or two and every time I tried to sit up I would feel more sick. I felt like I was being a baby and that I just needed to get up and so I stand up for about two minutes and start throwing up. It was really weird how I only needed to throw up when I stood straight up but if I was leaning on something it never happened....I probably threw up at most five times and I still felt dizzy and such for the rest of the day and the next. Now I only get dizzy when I feel like its hot. But someone brought to my attention that it could probably be pregnancy and not heat exhaustion like I originally though it was....should I buy a test?