Phone doesn't turn on or charge with empty battery
My phone's battery just died while charging. No idea how it happened, but apparently it wasn't charging at all, even though it displayed a charging icon.
Now it's turned off and it won't charge. When I plug it in, it turns on, displays the screen with the big battery, as usual, but only for a few short seconds. Then it turns itself on, even though it has no power, and shuts itself down immediately after it turns on, meaning it never charges. Then it goes t the big battery screen again, then turns itself on etc. and this goes in a circle for all eternity.
What do I do? I have no battery charger and I don't have any friends with a SGS3
(I'm running UltimaROM 17.1, in case that's related, which it might be, since I jut flashed it yesterday morning.)