Print quality has gone down significantly over the last two weeks -- fixes?

Hello,This is my first time posting here--any advice and help is much appreciated.I have a QIDI X-Plus that I've been using for about 7 months now. At first the prints looked fantastic, great for the prototyping needs that I had---very high precision and a very good surface finish. The best results I got were with the original roll of material that came with the printer (which I have been told is rebranded eSun filament?). I've successfully used a polywood/filled filament as well with fine results. Over the last few weeks however, the quality of the finished printed parts is terrible. I'm using the standard settings for PLA in the software, printing a small raft at the base to get good adhesion to the table. I'll attach a few pics to show the degradation of quality so you can see what the symptoms are.Am I seeing belts/etc getting worn out? Do I need to calibrate out some backlash in the different axes? Is that even possible? Help!