I'm trying to be happy. Stopping putting me down plz.

As I like to help people I find it difficult to be happy while helping others who are constantly depressed. It does wear me out. I can't keep being there for the same people who seek someone to listen to about the same issues over and over again while I myseld am trying, TRYING to maintain a positive outlook on my life.
It just irritates me, pisses me off when I have to talk to the same people over and over about the same problem. It makes me wonder if they are listening to a damn word I say in the first place. After wards it turns my positivity upside down. It... sucks.