Nearly fainted

My mums friend came round to do my hair everything was good everything was normal. I then sat down to get my hair done when I felt really thirsty I just thought meh I'll have a drink when my hairs done. I then started to feel really sweaty then my vision went really blurry and my mums voice (talking to her friend) went kind of distant and echoy like she was far away. I felt like everything was fading away. I then said 'mum I feel weird' and she quickly got me a drink of squash and as soon I drank it my vision had returned my hearing was back and everything was fine. I do feel kind of shakey though and I looked in the mirror and I'm extreamly pale. I also have had alot to drink throughout the day so i don't think I was dehydrated or however you spell it so meh it was pretty scary lol