C.H.
Hi F. - Let me start by letting you know that I have not been in the same situation as you; however, my heart is going out to you. I can hear the despair in your email!! You are a treasure for taking such good care of your parents and managing your household and trying to stay sane at the same time!! I have added you to my prayer list and hope that your burdens ease.
All that said, here are just my thoughts. You need and deserve an outlet. Since you have already found a group of ladies that you connected with, try to get back in touch. Maybe you can have a short playdate at your home - let them know of your situation and try to get them over for an hour just to hang out and relax and chase the kids around. If you can swing it, go out to dinner/a movie/a drive when your hubby is home. The ladies you met will understand and if they are as great as you think, they will make some time to support you.
If you truly cannot get away for even a short time, then just try to hang in there. This is a terrible time in your life right now, but it will get better eventually. You will have the ideal that you want, it's just not the right time now for some reason.
Above all, don't feel guilty (if you do) for wanting some time to yourself to be you...you are giving all of yourself to take care of everyone else and you need some refueling time. So, call/email the ladies you met, arrange a few hours for hubby to watch the kids (I know he'll be glad to see you smile after a visit with your girlfriends!), and relax for a little bit.
If for some reason your group doesn't respond well, I invite you to come check out our group of moms. We have a great group of caring, supportive ladies. You can see us at http://workingmoms.meetup.com/5/
I pray that all goes well for you!! Best wishes - C.