Most likely you’re either on the wrong account or wrong character bank. (Check the upper right of the launcher.)
Make sure you also check your shared bank for items as well. (Type /bank before talking to the bank teller.)
Hopefully you didn’t loan your account out to anyone and have them jack you.
Whatever the case, I do hope you’re able to locate your characters and items.
If you don’t, well, that would be unfortunate as we don’t do item or character restoration. You might ask the community for some loaner items or help getting some of the stuff back that you lost.
Good luck and I wish you the best!