Don't be to bent out of shape. Ignorance is its own reward, and that person was just ignorant.
I had a similar experience last summer when I used my handicap placard at my local grocery store. The heat and humidity of that day made it difficult to get in to the store with enough energy to do my shopping, so I used my handicapped placard to park close. When I came out, an elderly woman saw me getting in the passerger seat of my car and as she walked by said, "You're really handicapped, aren't you". She didn't even give me a chance to explain, she just kept walking to her car. I was really embarrassed. It made me feel like I didn't deserve to use the handicapped space.
But you know what, I got over it. I told myself that was her problem, not mine. If I need to park in a handicapped space to make my life workable, I will, and to hell with anyone that doesn't like it!
RRMS since 01/07.