Power steering pump or what ?

It snowed big time here Christmas night and I'm one of the lucky few that had to work that day ,anyway I'm in snow almost to my knees I get In 2002 GMC Envoy as I am backing out I get stuck had to put the envoy in AWD and wiggled my tires hard from left to right to clear some snow out from under my tires after I do this for about a minute I'm free from the snow drive home everything seemed fine until I turn into the drive way and the steering wheel is hard as hell to turn didn't thing neither of it because my tire was in deep snow .Next day I went to the store the road I was on had no snow but when I got ready to turn it was really hard making the turn .Since then I've notice things

1. Steering wheel is hard to turn

2.Steering wheel seems to turn all the way around in a complete circle if I keep turning it

3.when in park with the car off and the key out the steering wheel doesn't lock and I'm able to turn the wheels from side to side with no resistance especially on Icy surfaces

4.there's fluid around the reservoir cap and there reservoir looks over filled even though I haven't added any PS fluid in it since I bought 2 years ago

5.My Drive belt is got a lot of play in it I can turn it from side to side with my hand with no problem

what I don't get is if the power steering pump is out why is the wheels so easy to turn in park

Thanks in advance for all of your answer