Selfish...

My baby boy is now 3 years old!! We had a birthday party for him last night and I would put up pictures but the bestie took the pictures with her camera so I will have to post some later. I think he had a great party, and it was my first BBQ to throw and lets just say my feet are going to hurt for a while! It is so hard throwing a party together but in the end it was all worth it.
I have been feeling down about him turning 3 because well I thought I was going to have another baby by now and I would have but God had other plans for me. Part of me is wandering, I am being selfish in wanting another baby so badly. I mean, I know women who are having a hard time just trying to conceive there first child. I mean it wasn't easy with Elijah it took 2 years. I just feel like, I can't feel bad for not being pregnant yet or I cant get upset because it is most likely going to take awhile, because I already have a child. I am being selfish? I am not at the point where I am taking pills, shots or any other medicines to help me get pregnant so do I even have the right to feel like I am part of the "it hard for me to get pregnant group"?
I have also lost a child, I have felt that emptiness and the pain when you see an ultrasound screen and there is no baby. It is earth shattering because you just go home, because there is nothing you can do, you just go home and deal with the emotional pain and the physical pain. I may have never seen or held him/her but I still lost a child and it something you just don't forget about or push to the side. I get this feeling that people don't see that as a lost and that I shouldn't be hurting from it still.
So where do I fit in at? I am selfish? Do I need to just suck it up and not feel bad that I am not pregnant yet and that I should just be happy with my son.
I don't want other women who are trying to get pregnant look at me and think what is she complaining about she already has a child.
Just trying to figure out where I fit in at...