You are feeling what so many moms and housewives feel... it's normal and it's real. Don't put yourself down for these feelings ... you do need to acknowledge them and talk about them.
I want to encourage you that what you are doing right now is far more important than anything you did in the outside working world. Raising your children is, in my opinion, the highest calling a woman can have (if she chooses to have children). You are raising our next generation and your children will raise the next generation... so what you are doing right now has the potential for positive implications forever!!
You are working the toughest job right now that anyone will ever work. There isn't an Executive anywhere on earth that has a more noble and demanding job than raising our future Executives.
And, you are totally and completely way underpaid (monetarily wise).
I, too, left a really nice, respected job 19 years ago to raise our children. It was vitally important to my husband and I that we raise our children with one of us being home all the time. (I was even called by the President of the company I worked for a few months after I had quit, begging me to come back to a higher position in the company!) We have 3 special needs children so I totally understand and empathize with therapies and all that's involved.
There have been times that I've thought I had noodles for brains after only talking with little beings under 4 ft. tall for years. I became involved with a Home School group and became close friends with several women in our position who have remained my support and encouragement for all these years. I suggest you find a small group of women that can relate to what you are facing and get involved.
I'll be praying for you and for your family as you are facing a new period in your lives. God will give you the strength to face the new challenges facing you.
You CAN do it! You are a GREAT mom!