Newbase

Hello everyone, First off, sorry if this is not the right place to post. I was confused as to wether I should post this in the "resource" part or here, I apologize if it's not in the right place. I started having this issue with Photoshop and it's very annoying. Basically, when I add a stroke to something (a shape for example), it's blurry. Here's an example of the problem : As you can see if we zoom on a side .. The stroke is blurry, fading. I would like it to stay simple, only one pixel black stroke, no "fading" or "blur" of any sort. I didn't have this problem before so I assumed that I messed up with the settings, is there a way to reset them to factory settings? Thank you all for your help, it's very appreciated!