Having trouble getting pregnant!

Just worried I want be able to have a baby. Me an hubby been together 10 years, trying for 4 years, and married 1 1/2 years. I have yet to become pregnant. I don't really have a period, my last one was last year sometime. I have bought the Conceive Plus and only been able to use it once. I want nothing more than to be a mother. Anybody else having the same problem?