The pros keep saying "All you can do is get your chips in with the best hand " Losing is a part of No Limit and every other poker game. In short get over it , it does happen to everyone.

That is a tough one. It just happened to me - minimum raised in middle position with A6off, 4 players to the flop. Flop is : 7d Ks Ad and SB (15west107) bets 1200 and I raise with my 1420 all in. Since he was small blind, I put him on that four-flush. No diamonds for him, but I had him 2x covered, and made the decision he didn't trip.

it happen to me in a live turnamet i get 4-4 on the big blind (i have a solid image on the table ),2 in the hand the flop 2h 4s Qh.the small blind raise i re-raise dealer fold small blind goes all in i call i show the set and he show Kh-10h the turn 7s and the river 3h i i get out of the tournament the sad thing is drive tow and a half hours to play

You are gonna have to look at other factors before making a decision. First of all the flush draw is 38% to come not 33 %, secondly if there is a possibility of a straight, one of the best hands to have is an open ended dtraight draw as well as a flush draw. This hand is 62% to hit meaning that even if they are behind at this time they are a favorite to win the hand.
Some factors helping you to decide.Can your hand improve?
Do you hold any of their outs? What is their draw includes overs?

Absolutely it hurts, but it is the 67% of the time that you have to be happy with. They are risking their chips to succeed a third of the time. Keep playing the way that you are playing and you will be on the winning end more often than not!
If it is after the flop though you do have to wonder if they do have trips or they hit two pair. You have to find the way to call when they are only on the flush draw.