Waiting game of life

I have two boys now, one starting kindergarten this fall. I've been a stay at home mom so far, back story to that for another time.. Well, thing is, I want another baby so badly! My youngest just turned two and I know by the time he/she came around my so and I could support all of us but, my family has been disappointed with both my other pregnancies, and I do want to have a career established first. But this waiting game is so hard sometimes! I don't know how to curve my baby mind... Any ideas that might help?