People tell me 'don't try'

I'm 42 soon.More than anything in the world I would love to have a baby. For the last 5 months I have 'tried' to get pregnant by trying to calculate my ovulation times and having sex around this time. So far, nothing has happened. People say 'don't try' to have a baby. What does that actually mean? 
My husband works away from home also so I feel that it's never going to happen for me. I'm really down about it.