Shit happens. Some people just end up being so nice that they put themselves in situations where other not so nice people can take advantage of them. It's sad, but you have to remember that being a good person and telling people 'NO' are not mutually exclusive!

You can be kind and still be assertive and proactive, and get what you really need without hurting others.

I believe in some sort of karma too- that what you get out of life is directly related to what you put in. Try putting in something a little different, if you want your situation to change. Just adding a handful of dried herbs to the dough yields quite a different loaf of bread, ya know?