Are you an only child?....more inside.?

I have one Son and at this time I am not able to have anymore as much as I would like, the last 3 years it has not happened. I do want more but do know if I want to go thru all the time, money and heartache of the artificial process. I guess my question is are you happy as an only child, would you have liked siblings? I have 5 brothers and sisters so I do not have an answer for myself. should I try it so my son won't be alone once we are gone...do you feel resentment towards your parents for having just you? do you know what I mean....any answers would be great....thanks.