Re: My phones acting wonky
It sounds like it is spontaneously rebooting. Did you install any new apps or make any changes? I would try two things separately.
Removing the SD card.
Booting into safe mode.
See if it still happens after either of those. Also clear your cache from recovery. Next step would be a factory reset without adding anything to your phone afterwards - no restoring, no apps, no altering of settings, no SD card - just complete newly factory reset phone. A factory reset will erase all your data so back up anything you need. If it still occurs you should go to T-Mobile for a replacement (or Samsung if you didn't buy it from tmo).
Here's a link how to do the various things I mentioned: https://t-mobile.jive-mobile.com/#ji...cuments%2F9049