Why are you getting so upset at the thought of not sleeping? I wonder if stressing out about how much you're not sleeping is making you feel worse? I know that on the nights when I worry about the fact that my daughter is waking up every 2 hours that I feel much worse than the nights that I don't even bother to look at the clock. Last night she was latched on almost the entire night and I am not feeling like the nicest person today, but I know that she needs it or she wouldn't be doing it.
I see that you're worried about the amount you're pumping and that you're giving your son formula. When you give him formula you are telling your body not to produce that amount of milk.
I can't remember what you said in your other post - are you pumping at the same time every day in the morning to try to increase the amount you're getting out? That should help. Also, try eating oatmeal, drink lots of water, and check out the increasing your milk forum.
Lilah 10/08 nursed 25 months
Beatrix 01/11 nursed 30 months