My 8 month old female Giada started her first heat today(3 1/2lbs)

when she was 6 months old (3lbs)I took her in to be spayed and after they started general anesthesia the doctor said her heart rate dropped so he woke her up and didn't perform the surgery.

I have no intention to breed her so I want her to have the surgery for her physical health and my mental health!! She has removed her diaper repeatedly and I am finding tiny blood spots Everywhere!!!!! But after what happened the first time I am too afraid and have no idea what I should do! Please help!!