Drove car 2,000 miles past oil change date, no oil in car; have I ruined my car?

I very stupidly misread the reminder sticker for my oil change and drove 2,000 miles past my oil change date. When I brought it in today to get the oil changed, realizing my error, the mechanics said it was completely out of oil. However, at no time did an oil light come on (not sure if this matters, though). The engine ran fine, too, up to this point, but perhaps sounded a little rough at times.

Have I completely ruined my car?

It’s a ‘98 Nissan Sentra with 110,000 miles. Trying to figure out what to do.