If the feeling of unfairness sprouts in our gambling activities, we must stop gambling because it will only bring frustration, stress, and hatred which is detrimental to our health. Besides, once we think that it is unfair, thee simply means we are beginning to doubt the fairness of the game or the casino. I believe if one got the feeling he should stop playing on that platform because the feeling of unfairness is not normal in gambling games where we all know that the house has the edge and accepted that fact when we decided to play on that platform.
I do agree that increasing the wager will not affect the winning chance, it does affect the result of the amount to be won though.
if you are playing on a reputable site, provable fairness won't be a question. but if you are playing on a second-rate casino, that's when you will start doubting their provability. it is understandable about such feeling of getting duped. so yeah, if your instincts is saying something is wrong with your game, better stop and get out. don't wait to let your suspicions be reality. if you have the hunch, maybe, there's really truth behind such hunch. however, the amount you wager doesn't affect whether you will win or lose, so long provability is in play.
For me personally, just like you, I only play on reputable casinos, but sometimes, after losing for a while, I always feel like trying out some other casinos, though not entirely new casino though, but I look for a casino I am sure I've never used before to try my luck there, and i always make sure to try with a very small amount of money, all for fun anyway, i mean gambling has and is always fun for me, though i can not deny the fact that many a time, I've allowed emotion to push me into going overboard, but then, that's gambling, things like this are bound to happen from time to time.