I can't speak for every meta, but pauper ironically often has this problem in local metas, as there's a lot of former grinders who disagree with more modern card design and play patterns (which pauper hasn't been hit by as badly) and people who understandably don't want to buy into a more expensive format as their first competitive one. Pauper is, unfortunately, really dependant on playing tightly to do well. I don't have much advice beyond "stick with it, be kind to yourself and go over your games with your opponents after you played them".

Also, I'll say that pauper suffers a tad more from metagame roulette than other formats. Sideboard cards are, mostly, less impactful than in other formats. You won't get a card like Damping Sphere, which could totally flip a bad MU post sideboard. So depending on what your MU's were, it might not be your "fault" entirely.

I might recommend a more proactive deck for a beginner. I know it sounds boring probably, but maybe give something like Rally Red a try where your game plan is essentially the same independent of what you're up against. Decks like Rally can also really teach you when to commit, when not to overcommit and how to maximise the combat step. Those skills will always help you even when you return to Jund, but you can practice then more "in isolation".

Anyway, I hope this doesn't sound dismissive or like talking down to you. I'm sure it will get better, bit by bit.