Um... When I was young, my mom used to get cold water from the sink, and warmed it on the stove. Then she would put the water in a bucket, and use any type of box--for example, the one that you get medium sized dairy yogurt in-- and she put the bucket in the bathtub. (She did it all when she needed a shower,by the way. It might help you) She used the yogurt box to pour water on herself.

Hope this helped you. Good luck!