Couple questions, sorry if it sounds like I'm insulting your intelligence I really don't mean to:

1. Do you maybe have more than 1 character, or did you possibly accidentally create a new character? Maybe your original guy is still available at the loading screen. (I've done this.)

2. Are you using mods, like Valheim Plus? It's possible to lose inventory if you end up on a map without the + config, or sometimes the config file gets reset. (I've done this too.)