Screaming or howling in Belknap County, New Hampshire

I moved to this location in New Hampshire in 2001. I have had several sightings over the past few years. Usually from my living room while I am watching television. I know this sounds weird. But, I am serious. My couch sits facing my picture window. Beyond the picture window, there is a small creek and an empty wooded lot. I have seen deer, bear, turkey, racoons, moose and fox on my property. It is in a part of Gilford called Gunstock Acres. It usually happens in the late evening on a dark summer night. No paticular date or time. From the ground to the top of the window has got to be at least 10 feet tall. This creature is about 9 feet in height. Dark deep brownish long hair, and walks upright, similar to a human. I have seen it go one direction, then go past the window in the other direction several minutes later, or it just walks away until the next time I see it, which has been about once a year. I have seen it looking more like a shadow when my lights in the house are on. I am usually caught off guard, and am startled when I've seen it, in disbelief, but there is no other explanation. Last summer I happened to tell my husband and family that I saw Bigfoot again last night and my oldest son said he seen it the night before, passing by the window, and it looked right in at him as it was passing by. He described the same creature except that he saw the face. And he swears it is a Bigfoot too. He was creeped out about it, and I think he still is. My son is in his 20's. This is part of the Great North Woods, with lakes, mountains, rivers & caves. Plenty of places to hide. I have heard strange grunting noises, tree limbs breaking, screams, and walking sounds through my wooded lot. I refuse to go outside after I have seen it, and turn all the outside lights on, until I forget about it again. We have seen some huge prints out there in the winter going around the house, but they were unidentifiable. Due to the large amounts of snow we have gotten during storms, the tracks get filled in. I am spooked by it, but it hasn't done anything to any of us, except look in the window at us. I know what I have seen, and I haven't told many people as they would think we were crazy. So, my family and I would like to know what this creature is, and is it possible that it is a Bigfoot? We beleive it is, as we know what we have seen. It can't be a black bear, as this is too tall, and walks a distance on two legs and like a human, so it couldn't be a moose either. It is built like a really large broad-shouldered man, and muscular, but covered in hair. My son said that the face is hairy also, but the skin on the face is a lighter color than the rest of the body.