Hand1- I'm raising his donk bet in a 3-way pot. As played calling him down is fine.

Hand2- Even if he is stealing a lot in this situation I think you can probably just start calling him a lot lighter with position and this is a good example of a hand to see a cheap flop with in position. As played the flop is fine, although I would have bet more like $5 and then folded to his shove.

Hand3- I would bet more on the turn and then since his line is so weak I'd probably bet the river again but reads are important.

I get the feeling from the way you played and the bets you made that you're playing scared. Figure that out for yourself and try to be comfortable at whatever stakes you are playing.