I keep having weird dizzy spells?

It's happening more and more often, it starts out as a pins and needles / goosebumps type feeling in my hands and or feet then travels over my whole body and makes my mind feel fuzzy and swirly and also hot and it makes me feel like I'm losing control of my body for a few seconds. I had to sit down on the footpath at school today because of it that's never happened before. What's causing this?