I've certainly felt the same at times and made sub-optimal decisions. PLO is a game which you have to be mentally strong for because some days you're going to do everything right and still lose.
The game can really reward fish who will put in 100bb pre-flop with junk double suited hands and crack your aces which dominate them or call giant 4bets with stuff like Q932 single suited and hit the dream flop. It does make one wonder whether there's much point in trying to play premium hands when very often the bad ones are rewarded.
All you can do is try and make the best decision for each hand and hope it turns around (although there's certainly no guarantee as a person can run bad much longer than their patience/funds can stand). If you feel the quality of your decisions are declining then take a break if it's not something you can address during a session. Alternatively, perhaps try a lower variance form of poker? I see lots of NLH pros but not so many PLO ones - i'm not sure whether that's meant to tell me something!