Knocking in Perry County, Tennessee

I am an avid outdoors man, I canoe and camp on a regular basis, mostly by myself (nobody spends any time in the wild anymore). On my most recent canoe/camping trip I had set up camp started a fire, and and had just finished my dinner at around 9p.m. I had put my drinks in the water on the edge of the river and was walking down to the edge of the river to grab on, when in about ten yards of the edge I heard a big splash, something being thrown or dropped in the water, I didn't pay any attention so I kept walking, then as I approached the edge another even bigger splash was made and I could see the large rock that made it fly through the air hitting about ten yards from where I was. I froze and all the hair on my body stood straight up. I shined my led light over to the area and saw a set of eyes for about two seconds before they vanished. I fired my pistol to scare off anyone I thought would be messing with me, but no response, and this was on a week night where the possibility of someone roaming the area was not likely. I quickly packed my gear and left for home. The next morning I came back to the sight to look around and I heard something rustling in the brush, then I heard knocks in a steady patten of three I grabbed a piece of drift wood and knocked back. This continued for around five minutes, until I heard a car coming so I stopped because I didn't want to give any curiosity to anyone, and I didn't want anyone to think I was crazy. I left came back four days later and spotted a track. The track was around four-five inches longer than my shoed foot, which is a size twelve.