You are stronger than you think............tha t being said your instincts are telling you a change is needed to meet the needs of your family and future pregnancy. If you scale down on the number of children you can take the breather you need. Once you feel things and you are back on track you can always add more. Also, maybe you only want to do b/a care that would still keep money coming in and your time in between would be time for you and family.
I think every now and then we need to access our situations and see how things are working. Then you can make changes before your stress level hits the roof.
Take a deep breath and think..........a new baby.....how exciting