I felt like I was going to pass out (HELP?)?

I umm.. a couple days ago I didn't drink enough water for a few days and I was working out hard.. ( I KNOW THAT WAS DUMB) so then I suddenly felt weird and my ears I could barely hear like I just put ear plugs in or somethin and I felt exhausted.. my sight got all weird and black and my face turned all pail my heart started pumping really slow for a second until I started breathing hard again and i'm also very young i'm 14 and i'm over weight