i just started having a problem with all my texture packs including the default one where some textures are messed up
This is happening to all of the resource packs that you've tried? That's worrying. If it were just the default that wouldn't be alarming, but if it's doing it to all of them then that might be an issue.
Try the following, in order, checking to see if it still happens after each step:
1) Restart your computer (This should always be the first step whenever anything goes wrong.)
2) Update your graphics card's drivers and software.
3) Uninstall and re-install Minecraft. (BACK UP YOUR WORLDS AND RESOURCE PACKS FIRST!!!!)
4) Do a RAM test. (I don't know what OS you're on, so you'll need to find out how to do this yourself.)
5) Run an integrity test on whatever HDD or SSD that you're running Minecraft on. (Again, a web search is your friend.)
I can't really advise you further without more information. Being able to see your session log (.minecraft/logs/latest.log) might yield some answers but more than likely will not. Otherwise I don't think I can really do much more to diagnose your problem I'm afraid.