I think I am just wussy about how it's supposed to feel when you're actually exerting yourself; I get scared that I'm going to hurt myself, but I think I'm just wrong about that. I'm going to meet with the trainer once a week for the next three weeks (included in the gym membership) and hopefully that'll let me re-establish a baseline for what my body can reasonably do.
She asked what my fitness goals were, if there were any particular areas I wanted to target. I think she must be used to women coming in and saying that want to trim three inches off their waist or some such. When I told her I mostly wanted to get stronger and faster, she laughed out loud. But also agreed those were good goals. :-)
I admit, I also think I'd be healthier 20-30 pounds lighter. I won't weep if that happens too. But it's not the primary goal at the moment. Running up three flights of stairs without getting out of breath -- that would be AWESOME.