LG Phone will not boot normally

On Saturday, I had my phone charging on an external charging device in my bag. When I pulled my phone out and off the charger, it would not come out of sleep mode. The red light at the top of the phone would blink red but the screen would not turn to the lock screen.

I held the power button down to power off the phone which worked. When I powered it back on, the phone stuck on the Metropcs screen but would go no further. The person with me held down the power button and the volume down button. When the phone rebooted, it came onto a window that said 'welcome to fastboot'. It has only boot to this screen since. When I connect the charger it boots to that screen. No indicator lights come on to say your charger is plugged in. The phone vibrates, stays black and then shows that screen again. Model: LG Q7+