Struggling with the idea of only having 1

Hi everyone. It looks like my child is going to be an only child and I'm really down about it. I had 4 miscarriages before having her, plus I miscarried her twin. I'm technically pregnant now but its looking like another miscarriage (will know more Monday). We went through ivf to have her and are not able/willing to go through ivf again. I'm 37 and while I can possibly get pregnant naturally I'm not sure if I can maintain one - if it happens at all (my current pregnancy is the last of our embryos from ivf before). I really wanted 2. I feel like my child will miss out on the joy of having a sibling and will grow up lonely. I worry about her having to make tough decisions about me and my husband as we age. I worry about her being alone when we pass. There aren't any cousins her age in the area. I'm really really bummed about it.