my iphone restart repeatedly

There were rumors that people were usong a text to restart your iPhone automatically and it would tap into your phone to see your camera etc

Take a look at this article:

If your iPhone, iPad, or iPod touch doesn't respond or doesn't turn on - Apple Support

Try to reset your device. This won't delete your data stored on the phone.

• Press and hold the Sleep/Wake button
• Press and hold on the Home button
• Keep holding both buttons until the display turns off and back on with Apple logo on it.

If this does not help, restore your device to factory settings. Note that this will erase the data from your device.

Take a look this Apple Support article: Use iTunes to restore your iPhone, iPad, or iPod to factory settings - Apple Support.

Try the recovery mode. Turn your device off, then plug it to your computer with the home button pressed. You will need to have iTunes installed on this computer. Keep the Home button pressed until you see the iTunes logo on the screen of your iPhone. After that on your computer you should see the iTunes window saying your iPhone needs to be restored to factory settings. Click on the restore button.

More info here: https://support.apple.com/en-us/HT201263

if this doesn't help, try using the DFU mode:

• Connect your device to your computer using a USB cable.
• Turn off the device.
• Press and hold the Power button for 3 seconds
• Press the Home button while holding the Power button and hold both for 10 seconds.
• Release the Power button, but KEEP HOLDING the Home button.
• After about 15 seconds, iTunes will tell you it has detected a device in Recovery Mode.
• Restore your device

More info here: https://www.theiphonewiki.com/wiki/DFU_Mode