My io9 view has for some crazy reason has become ridiculously large as if i was blind as a bat. I have no idea how this happened (it was like this when i got home from work this evening. does anyone know how to fix this so its back to normal?

Edit: Thank you so much to everyone who responded. worked 12 hrs today (i move heavy machinery by hand averaging about 3 to 10 tons apiece on easy days) and only had 2 hrs sleep last night so i am brain dead. again thanks ya'll for your help