Feeling the pressure

This is cycle #2 ttc after miscarriage. Last month I got a bfn and was so sure that we had nailed it. I was so disappointed when my period came. This cycle I got a positive opk way earlier than I expected (cd 13) so we didn't have sex before, only twice that day. We will also try tonight just in case. I hope it wasn't too late. I'm worried that we missed the window. So I'm already stressed and my daughter just came to me and said, "Mommy I wish I was a big sister." It just crushes me. She walks around with her baby dolls and says that she's holding her baby sister and she talks about what she wants to name her sister. She wants a sibling and I feel so bad and it makes me feel more pressured because I want it for her too.