My phone keeps crashing when I connect to wifi or 3G, why?

I just updated my phone to the new ios8 system and it just keeps crashing. It only crashes when I have wifi or 3G enabled so I turned it on airplane mode and it stays on without any issues. I have tried restoring it but it asks me to turn off "Find My iPhone" which I can't do because it requires internet to do so. I've also tried turning off "Find My iPhone" on iCloud on my computer but no luck.

I have an iPhone 5, could it just be the end of its life and a coincidence that it happened when I updated my phone?