I can fully understand how you are feeling at the moment. I had a vertical incision too and felt just the same as you in the time leading up to it. It ended up not being half as bad as I thought it would be and if I can do it then anyone can! I agree with everything Tivoli has put above, do try and treat yourself and do some things you enjoy doing. The main things I took in with me were loose nighties, big pants in a bigger size (your tummy will be swollen), peppermint tea bags (an absolute essential for helping with the post op wind & bloating), nice toiletries, some magazines and my kindle.
I did feel a bit stressed beforehand and listened to some relaxation cd's which really helped. The time will soon go and you will be on the road to recovery. Keep us posted and we will give you lots of support to help you get through it.