Totally unhelpful comments in the first few responses. Clearly don't understand the heartache of not being able to have the family/family size you wish
@Mickey1234 frankly I dare you to go to the infertility board and say "just relax" you'd get rightfully hammered! It's thoughtless nonsense "just relax" doesn't cure endo, pcos, blocked tubes, poor egg quality, poor sperm quality, or any number of other pretty common fertility issues. I highly recommend that without commenting you read on here and elsewhere the experiences of those of us with gynae and fertility issues and perhaps get a better understanding of the grief and heartache it causes.
Op I lost 3 before dd, dd was almost lost and then it turns out I have a rare genetic condition that doesn't become apparent until the first Labour but which means any future pregnancy (even early stages) is potentially fatal to both me and the baby.
This meant dd was my one and only and the large family I dreamed of never happened.
It's deeply painful.
Op I would recommend you report to mnhq and have this thread moved to the infertility or conception board where I feel you will get far more understanding and compassionate responses.
being told “relax” and “be grateful you have one” is textbook crap people say to women with fertility issue
Totally agree
Akin to those of us who've mc being told crap like "well it obviously wasn't meant to be" or "at least you know you can get pregnant" 

Shitty things that belong on lists of "what not to say"!
Op are you able to access any therapy? I found therapy through the miscarriage association very helpful at that time and with another therapist after the news about the inability to have more dc.
It doesn't "cure" the situation but can help you come to terms in some way. Time helps too.
I am immensely grateful for dd and I love her to pieces, we have a lovely close relationship. That doesn't mean it doesn't still hurt that I was unable to have any more.
My dd is now 20, when she was little she didn't know I couldn't have more. She knew she was my lucky baby after mcs at an age appropriate point and later that I had a medical reason why i couldn't have more. Before she knew either she would say she wanted a sibling, ask why she didn't have one and I'd deal with it in a way that was suitable for a young child.
She has a disability herself which may impact fertility, pregnancy and birth and I've had to help her come to terms as much as is possible with that. Not easy for an adolescent girl to deal with. Given many adults don't cope with such news.
So sorry you're dealing with this op 