iphone 5
So one of my friends spammed texted me the effective power in whatsapp, and now I can't even open my phone without it resetting. It takes around 3-4 seconds of appearing at the lock screen before it gets reset again, and every time I try hard resetting it by pressing both the lock and home buttons my phone dies. I don't want to go get a new phone because of this. I just want to know if there's anything I can do to fix it.
iPhone 5, iOS 8.3