honestly... probably fine. It's really difficult to get into gear from 3rd to second if you're at a high RPM. So I'm guessing you were shifting at like 5k or lower, right?
At 5500k in 3rd, you're at redline in 2nd (ish)... which is not enough to kill the engine from over speeding. And if you did kill the engine... it probably would've gone out quicker than you would've had time to drive home and post this.