Thank you for your time.
As the title says, my device has started doing this for about a week. I can even have a fully charged battery, but if I disconnect the charger, within 5 minutes, my device screen will make some weird glitchy thing and turn off. I've tried multiple ROMs with no dice, so it's a hardware problem. I'm hoping it's just a battery issue, as I can't really afford another device at the moment.