Oh dear, do I know this one!
Even if you are a positive person yourself and you do try, it's sometime really hard to be around a person who is constantly negative and never happy, never see the positive in nothing. This person will bring you down because you get tired and the harmony of life is never present.
for if they are not happy then no one will be.
I understand what you are saying so very clearly. I wish you were not in this negative envionment because it's really not a good one.
I'm sorry!