Wow, you've got a lot going on! It's no wonder you feel overwhelmed and want to get organized. Don't worry, you can manage this situation. Let's take it step by step to get organized.
Number one, your husband. Once your baby arrives, there's simply no way you can continue to work, care for the dogs, get organized at home and also make breakfast for your husband and set out his clothes every morning. The sooner you both realize this, the better.
Pick a quiet time to sit down with your husband. Tell him how crazy and scared you feel and ask for his help getting organized. It's generally better to enlist him as a partner rather than telling him bluntly you're going to stop doing all the things for him that he's enjoyed so far. Caring for a new baby puts a huge strain on a relationship, so you'll both need to pay attention to each other's needs and concerns to maintain a happy marriage.
Write down all the household chores and how long each one takes. Decide together which of you will be responsible for each task. Make your life simpler by looking into a dog walker, asking to telecommute at least one day a week and generally, relaxing your standards for housekeeping. This is the time to focus on what's important: your family, not the cleanest kitchen on the block.
That brings us to your stepchildren. This new baby is going to rock their worlds. Prepare them for it by reassuring them that you and your husband will still love them as much as you do now, but that little babies need a lot of time and attention. Refer to the baby as "our baby" so that they feel some ownership, and make sure to keep doing the family activities they love, with baby in tow.
Good luck! I believe you can do it. You sound like the kind of woman who can handle all this with style.