when is it okay to give up?

My husband and I have been trying for a while, to have a baby. I'm at the end of rope and I don't think my heart can take much more. I'm so ridiculously bitter about babies in general now. I don't even get on Facebook anymore just to avoid the mass collection of baby pictures, announced pregnancies, ect. I literally just want it out of sight, out of mind. Is that okay? Does that make me terrible? Or is it okay to say " okay 8 years  is plenty long enough to do this to yourself. You can't keep breaking your in heart!!" Is it okay to give up?