[CLIENT] Apparently I have negative IP...?

After buying Dr. Mundo with IP, my balance dropped to -1157, even though I had enough IP to purchase him. When I try to purchase a champion by pressing the button in the bottom right of the "Purchase Item" screen, the balance drops even lower. IP Balance: http://prntscr.com/847782 Buying: http://prntscr.com/8477e7