Is Being an Only Child a Bad Thing?

I love my siblings.  They taught me how to share, love, argue, fight, bullshit… SO many things. And because of that, I always said if I ever had a child, I would have to have to have another, because a sibling is the greatest gift a parent can give their child.  Now here I am with one child, not really that interested in having another. I feel awful about this. Awful. For as long as I can remember I have had these preconceived notions about only children, and that whole idea about siblings being the greatest gift ever. Now look at me, feeling quite torn about giving my son this great gift...

I feel like I am a horrible selfish mother for not wanting to have another baby.  I feel like a horrible selfish wife, since my husband would LOVE to another baby.  But when faced with the idea of having another baby I want to run to my closet and hide.  Plain and simple I am afraid. Terrified.

I am terrified that I will not have enough money to comfortably raise two children.  I am afraid that two toddlers will be more than I can handle.  I am afraid of all of the unknowns. What if the two children grow up hating each other and never speak like some siblings I know.

Another issue I am having is that I have finally gotten the hang of this whole mother thing. I JUST came out of the first year fog! It's nice having a routine and sleeping 6+ hours again. Plus, Oliver is at a point where I can relax a little while he plays by himself.  I just don’t feel like I am ready to throw another baby into the mix.  Maybe ever?  Which is not a good thing since FTD and I are no longer spring chickens, so if we are going to have a number two we, I, need to shit or get off the pot.

This is something that is really tearing me apart. I want Ollie to have a sibling, I do. But… 
  

I also think that since he has four cousins that are all boys ranging from three weeks younger than him, to five years older, and in Australia he has three cousins, with another on the way, he won’t be short of family… However, I know a cousin and a sibling are far from the same… Or are they?  I don’t have any cousins, so I really don’t know.

Oh, what to do...

Is it a bad thing to be an only child? Are you an only child? Or are you struggling with the same issue? Did you have a number two against all odds and everything worked out brilliantly?  Do you regret not having another baby? I would LOVE to know your thoughts!