Thanks all so much for weighing in!
I have to stop pumping because (1) I just cannot take being a slave to the pump anymore - every three hours (except my long night stretch) to pump has really had me tied to the house - but I knew it was the right thing to do, so I did it. (2) I'm a math teacher, and my planning period next year is not until the last period of the day, and 3 days/week I have lunch duty (only 30 minutes long, and my pumping with set up, pumping, and cleaning takes 30 minutes)... it's just not feasible.
Thanks for the breast feeding suggestion too, but I had to give that up at 4 months. I tried to exhaustion to get DS on the breast again as recently as a month ago, but it never worked, so that is why I continued to EP.
It sounds like there are more pros to formula for a while (which I'll do a 50/50 with my milk to my milk last longer) before moving to the cow's milk. Are there formulas any of you would recommend?