The best advice I can give is that you build a strong support structure. This can include a spouse or significant other, your family, friends, doctors and specialists. All of these will play a vital part in helping you to maintain your health and sanity, as well as allowing you to best provide for your child. Next I would say get a hobby for yourself. You need something that is yourself. Something that is all for you and gives you an escape from the day to day tribulations you may face.
Next I agree with ng0208 in that patience is a must, there will be frustration, anger, and hurt. No matter what never take it out on the child, never let them see it, and never let them feel it. They must feel only unconditional love and assurance at all times. Just like msburgman I too have an autistic child and if there is one thing I have learned it's that sometimes you will want to scream and run away.
Make sure you do sometimes. Take time off. Get that support and make sure they can help you to take care of yourself. You are no good to anyone if you are down, depressed, or sick. Take care of yourself or you won't be able to take care of your child. God bless you and I will pray that he gives you help, comfort, and peace through all of this.