Screaming or howling in Cherokee County, Oklahoma

In the summer of 2000 I went with my stepfather and his friend to some land (40 acres) that my mother inherited from my grandfather. It’s in a fairly remote and sparsely populated area near Lake Tenkiller. My grandfather had bought the land because we went to the lake multiple times every year when I was growing up, and fancied building on it. He passed away having never done anything with the land. We were going to clear a “road" from the public road to as far as we could go to the back of the property. That meant clearing brush and cutting trees (with chainsaws). We arrived around 9:00 am and began work. We took a break for lunch and I decided to explore the rest of the property while they sat in the truck and ate. At the back of the property (approximately 150 yds from where we were working) the land dropped steeply into a canyon/ravine. It was pretty clear all the way to the bottom and probably 80-100 feet of vertical drop. As I neared the bottom I saw what looked like a cave on the opposing side. That side of the canyon was much steeper and nearly solid rock. I walked down to the cave entrance and looked inside. I quickly realized it had another entrance as it was fairly well lit (being noon during the summer). The entrance I was looking into was about 5 feet high and 3 feet wide. I couldn't see the other entrance from it as the cave made a curve. I went inside and realized something had been living in there. The other entrance was about 30 feet from the first and roughly the same size. In the middle of the cave was a large “nest". It consisted of a shredded (filthy) sleeping bag, various pieces of cloth, grasses, and leaves. It was clearly fashioned into a large sort of oval shaped nest about 6 feet across. There was a few pieces of torn up trash scattered around that was mostly food wrappers. My first thought was maybe a homeless person was living there. That would be really weird though because it is miles to any towns or even campgrounds. There are a few nearby, the nearest being about a half mile away. I began to get a very uneasy feeling. I went out the other entrance/exit and decided to go back and tell my stepfather what I’d found. I was about 25 feet from the cave when I heard a “huff", like an animal snorting. I looked back and up the hillside above the cave probably 30 feet up I saw the head and shoulders of what can only be described as bigfoot. It was looking over the top of one the big rocks covering the hillside. It was covered in reddish/brown hair and didn't look like a human or an ape, more like a cross between the two. It was looking directly at me and I turned around and ran screaming back up the hill towards my stepfather and his friend. When I got back to them I was out of breath and huffing and puffing and trying to tell them what I’d seen. They laughed and told me I was full of crap. Despite my frenzied insistence, they didn't believe me. They said they thought we'd cleared enough “road" for the day and we'd come back again another day. Well, we never went back. It's a 2 hr drive from where we live in Norman and my mom decided it wasn't worth the time and effort. As far as I know, she still owns the land but none of us have been there since. I will never forget that day. No one I know believes me, but I know what I saw. I'll never go back there without at least a pistol. Whatever that thing was, I got the distinct impression that it didn't like me being in it's cave. Visiting Lake Tenkiller many times over the years I’ve heard and read of many sightings in the area. I always thought they were kinda kooky, probably just people mistaking deer or maybe even a bear for bigfoot. I'll never doubt them again. I'm 52 years old and I know what I saw that day. At times I've tried to tell myself that I was mistaken, but I realize I’m just trying to make believe it didn't happen. But it did happen and it's something I'll never forget.