2006 Scion XB Transmission Problem?

[Cody M]

My dad drives a 2006 Scion Xb. I was driving it in the snow and drove through my yard. The snow was just deep enough for the bottom to scrape along the snow lightly. At one point it snow got higher and it got stuck.I rocked it back and forth and finally after a few minutes of inconsistent tire spinning i got it out. It is a manual, but while rocking it back and forth i wasn't ridding the clutch, but just rocking it out by shifting from first to reverse quickly. Now when driving the car, it cannot go into second without grinding the gears. It doesnt do it in any other gears just second. Its a 2006 with 17000 miles, so it is still under warranty, but i was just wondering what you think is wrong with it.

Thanks in advance!