Im 11 weeks and only a sac is showing 😢😢

Im supposed to be 11 weeks pregnant with a rainbow baby but last week we went to our 1st appointment and there was no baby only a sac showing so doctor ordered blood work i went that day and my hgc levels were 27,000 on Thursday i went again an they were at 21,000. I've been bleeding off an on since yesterday. I went to my follow up appointment today and doctor sent me to the hospital for more blood work and to do a higher quality ultrasound. He's pretty sure it's not a viable pregnancy though but he wants a second opinion to be 100% sure before we do anything further. I have two kids already a boy and a girl but we've been wanting an other baby for so long. It's all so heartbreaking still. I feel like im failing like my body is failing. Im in my 20's it shouldn't be this hard to have another baby. I dont know i guess really i just want some hope. I want to know if anyones gone through this and ended up with a healthy pregnancy.