Since When Have I Been This Out of Shape?

The weather has been so nice that I like to put the kids in the stroller and go for a walk. Sometimes we go to the elementary school around the corner, sometimes we go out to the rec center (about a half-hour walk), and sometimes we just bum around the neighborhood and wave to the people. It's the same route we've always taken, since Elena was a baby. There aren't too many hills--most of the time everything's very flat--and there are plenty of trees to shade us. Why am I wheezing like an asthmatic pug after only 10 minutes? I swear I could go the whole way with only the tiniest bit of puffing just a month ago. Mind you, I am pushing 40 lbs of stroller, and another 60 lbs of children, but those numbers haven't changed much in the last 4 months. I guess this goes along with the fact that I can only pick up toys for 4-5 minutes before the nausea gets to me. Which would be why my visiting teachers came to help me clean my house today, but that's another story. It's a shame about the walking, though. It's just about the only time I don't feel sick.