iMessage turns off on its own, can't be turned back on
I have an iphone 5, and starting this morning none of my texts or imessages would send, and I can't receive messages either. If i turn my phone off and back on, messages will send and receive like normal for about the first minute that it's on. After that if i go into settings -> messages, it appears that imessage has turned off on its own, and can't be turned back on. Basically I've had to restart my phone every time I want to send a message, and when I do restart it, messages finally pop up that had been sent to me hours ago. I have tried resetting my network settings, toggling the imessage on and off (it won't let me do that though), a hard reset, and restoring to factory settings. Nothing has worked and I'm not sure what else to try.
iPhone 5, iOS 7.1