Update to Photoshop causing problems

I am brand-new to Photoshop Elements - using the free trial of Photoshop 15 on an iMac with Sierra.  The third day using it, I got a message that an update was available to 15.2.  It said it contained bug fixes, so I downloaded it.  Since then, my editor hasn't been working right.  There is at least a 3-second lag time when I

click on something, the + sign for the clone tool doesn't always show up, and the circle that represents the brush flashes a rainbow of some sort and doesn't always respond to the slider with the correct size brush.  In addition to that, the clone tool doesn't seem to work as well as it did before the update, and sometimes when I use the zoom tool to enlarge, the picture "jumps away" and gets smaller!  Also, it no longer scrolls smoothly - it's very jerky.  I was in the middle of editing a very important heritage photo, and I don't know what to do!  Can someone give me some suggestion of what might fix this?  It's really frustrating!  Thanks!