We have a 4yo DD who was conceived the first month of trying but have been TTC baby no 2 for almost 2 years now.
I just got my period this morning having convinced myself I was experiencing all kinds of pregnancy symptoms for the last few days 
DD loves babies and has started asking brother or sister (although she's generally a very happy child) so I feel guilty that I may not be able to give her one but I need to prepare myself for the possibility that baby no.2 may not happen for us and she may be an only child.
DH and I are constantly being asked "when are you having another??" as though I can just click my fingers and make a baby appear! When I say "we'll see" or "we're not sure yet" etc (because I don't want to go into the whole sorry saga of my possible secondary infertility), we invariably get told that "DD needs a brother or sister!" , "Surely you don't want her to be an only child!" or worst of all "an only child is a lonely child".
We are very lucky in lots of ways and the three of us have a lovely life together. I would like to just appreciate what we have and not worry so much about it all but I am finding that all the negative stuff people say about only children is making the situation much more difficult for me to handle.
So, please MN, can we have a thread with positive things about being an only child or having an only child??
Also any advice as to how to deal with the aforementioned comments would be appreciated, bearing in mind there are some situations where "fuck off" isn't an option! 
Thank you.