Yes it sucks a lot when that happens...
Some situations, unfortunately, are very competitive which means that everyone involved has to put themselves first. This means that you have to be willing to trample over the competition and not feel guilty about it. Basically you have got to have a nasty personality. It is why sometimes the jerks do rise to the top - promotions, achieving success, etc because they don't care about hurting others... That's what makes them jerks. These are probably the same types of people that have done you some "dirty shiz". Thankfully not everyone is willing to do this, but then that means they will end up at the bottom of the social pile.
Also getting screwed over or being "broken", as you've put it, doesn't necessarily mean you are too sensitive. You're not too kind, they are too mean.