When I'm ingame my clan tag is never next to me, and it usually is but not recently...

And the "quit" button was removed from the "Your Clan" page?

the reason you cant quit is probably because your clan is in a war but i dont know why the clan tag isnt showing maybe its too long idk

You can't see your tag in Singleplayer but in Multiplayer you can .
and try to /rec if you were just invited to a clan , that might be the reason for not showing the tag .
also the quit button isn't available when warring another clan.

Thanks