How can I help my child deal with my stress?

Depends on age. Very young children feel your stress when you become angry or are unable to carry out normal activities--ie their meals, structured sleep, play etc. So despite your stress keep their day as normal as possible, if you feel angry or abusive, get help, separate yourself for a short time. Older children, be honest with them, try to give them some task to help you, and praise them when they do.