Changing settings for brushes changes all brushes

I have an issue which has rendered my photoshop useless. Whatever I do, all my brushes have the same settings. Which means they all have the same size, same shape, texture, diameter. Everything! I'm a stressed student and not being able to draw for classes will make me fail. Am I just stupid or did the whole new update screw up everything? Please help me, i'm loosing my mind.