Fairly standard river spot, i know i'm beat but i have to call because i feel its unfair he's drawn out on me.. I turned a flush board pairs on the river and he shoves all in for pot i know i'm beat but i have to call anyway..

I'm not talking about a specific hand but just a general position i find myself in, so many of my sessions are losing sessions because of this dumb mentality. Is there any tips to begin to get over this stupid thinking & mental block?