2005 Chevy Aveo transmission leak

My car sat in the parking lot for 3 weeks and was buried in snow and ice I dug it out and it cranked up and it was shifting perfectly but wen I got it out of the space it stopped and wouldnt go into gear and wen I try to put it in reverse it grinds well I couldn't see any visible signs of brokeness other than transmission fluid on the ground where it was parked and a puddle where it was sitting