Donking away chips on river

[nigul]

Of course it's easy to say he had trips on turn after seeing the showdown, but I just guessed it after a call on turn. After rethinking it was obvious that he will call pot bet on turn only with full-house, otherwise it was pointless for him to try to draw at all.

Forget about my silly question, I just wonder if I'm loosing due to making big mistakes (like in this hand) too often or just loosing small pots frequently. Can it be somehow taken out using PT?