Sweetheart, you are focused on what you don't have, instead of what you do have. The dream of a second (or in some cases, even the first) child is a big one, and well worth dreaming for most women. And the loss of a dream does hurt, and does require grieving, just like any big loss.
I'm in my mid-60's now, and have plenty of experience with lost dreams, large and small. I'm also friends with lots of older women, and ALL of us have suffered tremendously in our individual ways over lost dreams. I know a few women who struggled mightily over never being able to conceive, or not being able to carry a pregnancy to term, or not having as many children as they had hoped.
And the good news is: they were all eventually able to let go of what they couldn't have. They had to, in order to fully embrace what they did have. Some recognized dwelling in loss as mental illness of a sort. Some found alternatives, like adoption, or becoming the "honored aunt" to the children of siblings or close friends, or volunteering to hold babies in hospital nurseries. They were all able to finally let go of the dream that couldn't happen.
And they all report similar discoveries: That shift began when they were able to start taking in the bazillions of blessings that revealed themselves every single day. Moments of love and grace and beauty. In your case, I wonder if really allowing yourself the many joys of raising one healthy child would help you. Every time you notice the ache, immerse yourself in the memory of carrying and giving birth to your daughter, the preciousness of her tiny newness, and, even more important, the whole reality of what she has become, and the myriad ways she continues to change.
I raised one daughter, and we were so happy in so many ways. I was able to give her all my available attention, and whatever resources we had were hers. Even though we were pretty poor most of the time, she LOVED her upbringing, so much so that she wanted to have a daughter so that she could be to her child what I was to her.
She had a son, and so her experience is somewhat different than she expected, but we all adore him and she knows how blessed she is. She's decided to stop with one child, and he's happy not having siblings. Single children have some considerable advantages in life, and are not necessarily lonelier or more spoiled than kids in larger families. So it's not necessary, and not even a good idea, to have kids "for" their siblings.
I know your emotions around this are strong; I hear them in your request. You are allowed to have those feelings for as long as they serve you, but it sounds like they are serving only misery now. And I hope you will be able to hear this: as long as you keep feeding the anger and sense of deprivation you feel, you won't get to anything happier.
Anger like that is, in its own way, a temper tantrum. Hard to hear, but watch those moments, and learn from them. I KNOW it feels like it's happening TO you – I've been there quite a few times myself. But if you start paying attention and asking yourself questions about it, you will gradually discover that you have far more choice than you believe.
Here's one beautiful source of healing for many, many people: visit www.TheWork.org and watch the videos of people questioning their thoughts. Download the free worksheets that will allow you to try it yourself. Ask those questions and answer them sincerely, and I can almost guarantee, you'll start feeling lighter.
Your daughter needs a happy mother. She needs to know she's "enough" for you, or she'll enter her adult years with her own unexplained and unappeasable hungers. She needs to see how you approach life's disappointments, and blessings, so she can learn how it's done. Think about what you want for her, and take yourself in hand. Your life can truly be happier than what you're feeling now, but you have to want that, and allow that, or it will take much longer.
I truly wish you the best.