This looks very much like motion blur, caused by the camera being moved during the exposure. I seriously doubt the shutter speed was really 1/800 s. Is that just what you thought you set it to, or is it what the EXIF data says? If the latter, there is probably something wrong with your camera.

Note that the blurring is more a horizontal smear than actually out of focus. The focus was probably reasonable. At the time the picture was taken, your hand was moving the camera a little, in this case horizontally. The width of the streaks indicates how much the camera pivoted during the exposure time.

Nobody can hold a camera absolutely still, so there will be some combination of focal length and exposure time above which the inevitable camera motion from hand-holding will become apparent in the picture. A very rough guide is that exposure time in seconds should be the reciprocal of the focal length for a full frame sensor in mm, or less. For example, for a 50 mm lens you should try to keep the exposure time to 1/50 s or less. That's for a full frame (36 x 24 mm) sensor. For a 1/4 frame (18 x 12 mm) sensor, you'd need 1/100 s. This is of course just a rough guide, and your technique when hand-holding can make a significant difference. You should experiment to find what you can get away with and what you can train yourself to do.

If you are just free-standing, spread you legs a little, take a deep breath, let it out a little, tuck your elbows against your body, use one hand to hold the camera and press the shutter button, and the other to support the lens. When you press the shutter button, be extra careful to only more the finger on the button, not generally tighten up both hands or something. This may take some practise.

Avoid free-standing when possible. Leaning against a tree, wall, or lamp post, etc, will help your stability, which will allow a slower shutter speed with all else being equal. Even better is to be able to partially support or rest the camera against a stable object, like sideways against a tree trunk, or lying down against the top of a boulder.

Of course the ultimate solution is a tripod. That's basically what they are for. A monopod is a compromise that still gets you some of the stability of resting against the ground, but more freedom of movement, which is often useful for following fast action like a sporting event.