I know that you are posting from your phone and so looking things up online is not easy, but I found this:
"After you call the vet, make sure your horse is as comfortable as you can make him or her. Don't let him roll, but he can lie down. "
It was taken from here Colic - The Signs, Symptoms and Treatment - How To Recognise Horse Colic
Obviously you are more concerned with your horse tonight, but please update us when you can, you can worry about thanking for any advise you get here tomorrow.