If you try to take an indoor photo with lamp light only, not using the flash, you cannot work with ISO100, like apparently you were doing. You say it was sent to ISO800, but why then do I see the 100 in the photo of the back of your camera? That low light and low ISO will give you a hell of an exposure time (as you found out for yourself), and not even going wide open (f1.8) does really help! Even a speed of 1/8 sec. is really long to hold the camera all still in your hands! If you want to work with such light conditions (difficult!), you really need to up the ISO a lot and either live with the resulting noise or contemplate putting your noisy images through noise reduction (which reduces noise, but unfortunately also the picture quality, which doesn't show much in small pictures but would in enlargements). F1.8 gives you a very shallow DOF only, so often, when your subject isn't precisely opposite you, you get parts of it no longer focused, too. Or AF doesn't find your desired focus point, even at the best of your attempts (I had that happen, I did have the focus light exactly over the eye, quickly recomposed by leaving the shutter release pressed halfway, and I still found out later that focus had shifted somewhat! In a still object that couldn't have moved in the meantime).
So: low light = very high ISO (noise), aperture not as widely open as can be (i.e. f4 instead of f1.8), and a tripod if needs be (i.e. if the resulting exposure time still is too long for you to hold the camera steady).