I've been having this problem on and off for the past two weeks. First, my clock gets skewed for some reason (I never change date or time). Somehow it always starts with that. Then, I get to a point where I send a text message, the sent message doesn't show up in the conversation, but I know they get it because I'm getting my replies to what I originally sent. Then, somehow, it corrects itself (it took almost a week the first time), but now it's right back to not showing any of my sent messages and I need those.

Here's what I've done to troubleshoot so far:
1.) Deleted old threads I didn't need.
2.) Combed through current threads that I have now, saved all of the multimedia (picture) texts and saved what I needed to my phone and proceeded to delete the messages.
3.) Cleared my cache.
4.) Rebooted and restarted my phone twice.

If anyone has any advice on this I would greatly appreciate it.