Hi Jennifer. You've joined the right group! In no time, you will be saving tons of money and stocking up on items your family needs so that you will, hopefully, be able to live one income. You'll be surprised at how much of your "needs" suddenly become "wants" and are no longer necessary when you make the decision that you just HAVE to stay home with your baby.
One of my goals was to stockpile at least one year's worth of non-perishable items (HBA, paper products, laundry products, etc) so these items wouldn't strain our budget. You could set a goal to stockpile diapers, wipes, etc as well.
My suggestion is that you set goals and objectives and discuss this with your DH and keep that dialog going on a regular basis. Maybe it's not feasible to stop working right now, but you could set goals together to enable you to do so in the near future.
Good luck to you, and congratulations on your DD. I will keep your family in my prayers- it really does change things!