RE: I recently smacked my child...I feel horrible...
Get help. Please. Make a plan for it to never EVER happen again. Sadly, the chance that it will happen again if you don't get help is pretty dang high. Not saying that to be mean but to be honest. Solving this problem or any family violence is not something that can be done alone IMO.
We have all been stretched thin by our lovable rascals from time to time so I totally relate as can any *honest* parent. There is a reason Toby's room is safe and has a gate- I have one more than one occasion plunked him down in there for a few minutes with his favorite toy while I go relax on the balcony while chanting "I own a carpet steamer for a reason" or some such mama mantra.
In addition to a regular sitter and more help from you husband:
-see your doctor or a therapist
-consider taking a parenting skills class with other parents that have kids the same age.
-Join a parenting support group if possible.
-Make a plan. Who can you call if you are getting mad? Could a grandparent or frined come over on an emergency basis? Could a mother's helper drop in on an as needed basis so you can go into the other room to unwind?
You already know that your actions were wrong, so you have made the first big steps in fixing the situation. Don't dwell on the guilt, dwell on the solution.
If you PM what city you live in I can furnish you with a list of resources, as I used to work in the field of parent support.
Katie, mama to a pair of boys one little and one not so little.
"No American president has ever supported a major expansion of civil rights that has not ultimately been adopted by the American people - and I have no doubt that this will be no exception. The march of freedom that has sustained our country since the Revolution of 1776 continues, and no matter what setbacks may occur in a given state, freedom will triumph over fear and equality will prevail over exclusion." -Michael Bloomberg