Footprints in Jackson County, Illinois

I was out mushroom hunting and had my small son with me. I was standing on a small hillside. He was standing on the other side of the creek behind a tree which I didn't know at the time. I had my back to it, my face was facing the road. I had found some mushrooms, I was bending over picking them and I seen flash of movement behind me which to me kinda looked like a grape vine, because I wasn't focusing on the actual creature. And it looked just like a grape vine had moved briefly up the side of the tree. Then I seen a bigger part of it step out from the tree. I seen its knee and its shoulder and went on up and seen its face, which was hairy from top to bottom. I didn't see anything that would resemble a flesh tone. It was black. I saw it's eyes blink. It had white around it's eye, I could see that part. I guess there might have been lighter and darker colors on its face but it was all hairy. When I raised up and turned around to look, it stepped behind the tree where I couldn't see it any longer. I grabbed my son and ran to the car fast as I could and went home and got the shotgun and went back down there. I found some footprints where it had stood on the side of the creek and that was maybe 30 yards from me. This was the scariest thing, the most ominous thing, I didn't feel like it was going to come and attack me. It was probably as freaked out as I was. We went our separate ways immediately.