Exclamation Phone Continuously reboots need help!

What basically happens is the first time i was doing something and i guess my phone decides to randomly bring up the boot menu with, screenshot shot, airplane mode, power off, reboot, etc, so i click that to go away and continue what i was doing and it just reboots on me i don't even have to click the lock button anymore and it does that and this all happen randomly out of nowhere can anyone help me
JB isn't Justin Bieber, it's Jelly Bean