Surgery in two days - how to mentally prepare?

I have my surgery in two days, not sure about all the terms, but I have dysplastic spondylolisthesis in L5, so they'll fix it to L4 and S1.

I'm trembling, I'm terrified, I'm crying all the time, I feel kinda sick from anxiety. Usually I can stay calm in stressful situations, but somehow this has gotten to me. Is this normal? I feel like I'm breaking down. And I'm normally so focused on health and mental balancing myself, but I just can't. I don't know what do to with myself.

I do have a good support system and my home is ready for me to get home after surgery.

Please any advice so calm myself and get ready for this.