The game is still in beta? Make sure you "save" often by duplicating your gamesave folder because every few minutes you could lose the last x minutes of gameplay? I have no idea why you're losing barley and flax but if you're that worried about keeping it then at least protect your game saves folder by copying it where the game can't overwrite it.
I don't think your proxy server or steam or opera had anything to do with your trouble.



/mild rant
The developers have a strong idea (I Guess) that people want to play this game like a "roguelike" where you're going to just accept all the bad things that happen to you.

Meanwhile 95% of the players who still pay attention to Valheim look at it like a minecraft survival game (because the twitch.tv streams like to build cute viking towns) and it's "cute" when inept players with the right looks struggle through. Eventually the devs will catch up to this and the game will improve or die on the vine like every other independent game that went the cute twitch.tv route.

You just found out that the developers aren't building the game the way you thought they were. That's OK just now because if you're on PC you can just at any time copy your savegames and reload them. Your barley and flax are long gone, but whoa, you can recreate them with commands. Google it. Console players can't do this (usually). Maybe someday the game will work the way you expected and you'll be able to just save and load as you see fit, but right now that requires 1: a PC and 2: willingness to put in the tiny effort of saving/copying files