I know how you feel. I am not a stay at home mom, but I do feel like I never get any "me time." I wake up, feed the baby, pump, go back to bed for about an hour, wake up again, feed baby again, get ready for work, get Layna ready for the day, get bottles ready, drop her off at her grandma's, go to work, leave for lunch(I normally stuff a sandwich down my throat and wash it down with some water), pump, go back to work, get off work and go pick up Layna, feed her, pump, eat dinner, play with her (tummy time, bath, etc.), feed her again, get her ready for bed, pump, go to bed and start the process again. So, even though I don't stay home, I feel what you are saying. I have told my hubby that I might need one night a week to go out with my girlfriends or something. So, another new mommy friend of mine and I are planning a wine and cheese night on Wednesday nights. The babies stay with the boys. We haven't started that yet, but just looking forward to it gives me some sanity. Also, my husband and I are realizing that we never spend any alone time together and that is very important in a marraige, so we are arranging 1 night a week (a weekend night) to drop the baby off at my mom's and go on a date.
What I am getting at is that you need to make yourself a priority as well. I know that as a mom our entire world revolves around our kids, and we feel guilty if we stop to think about ourselves. But, if we are running ourselves ragged, then we are not doing our kids any favors. They only see mommy when she is tired and maybe a bit grumpy. It's good for the whole family for you to have some time to do what YOU want to do. See if you have a friend or family member that can watch your kids one day a week so you can have a day to get done what you want to get done, or simply relax. Then, I would also highly suggest planning a night for you and your spouse to spend some time without the kids. It's so important and I think if you can work those two things out, then you will find some balance and feel a little more sane. Good luck to you!!