Don't beat yourself up on that last hand. He would have likely shoved with any overpair.. so you are only really losing to 3 possible pairs.

As for calling when you know you are beat.. you have to get out of that mindset. Sometimes you have to call when you are even 80% sure you are beat, and sometimes you have to fold even when you are pretty sure you are ahead.

Remember to put the guy on a range every hand. it makes calling/folding decisions infinately easier.

Also a lot of times you are at the river having to make some crying call when maybe the hand should have been decided on the flop/turn. Make sure you reraise with confidence when you are more than x% sure you are ahead.. fold equity is your friend. Don't become a serial caller, its a losing proposition. Raise for value!

Tj