TTC baby #2

We have a three year old son who turns four in September, and we have been praying to add another little one to our family soon. We started trying last June and we still haven't conceived. I am so impatient and heart broken over it. I know it seems selfish but at the same time I want our little guy to be a big brother and to have someone to play with and grow up with. We have been keeping up with my cycles and fertile days and still haven't gotten anywhere :( I guess it hurts even more because we are beyond prepared and ready for another little one.