Vintage Sears Kenmore Sewing Machine Won't Sew?

I have a vintage Sears Kenmore sewing machine (no. 158.17032) that I've been using for almost a year now. It's in pretty great shape despite not having been oiled in a while and was working wonderfully up until yesterday.

I finally found a manual and learned to thread a bobbin on the machine, but when I attempted to do so, the bobbin didn't wind. I could hear the motor running, but nothing was happening, so I just assumed it needed to be oiled and figured I would do it later. I reset the bobbin winder latch and the button and rethreaded the machine to continue sewing with a bobbin I'd filled earlier with another machine.

I started sewing and everything was fine, but about 30 seconds in the needle stopped moving in the up position. I pressed the pedal and could hear the motor running, but the needle was completely still. I double checked the bobbin winder, shuttle, and rethreaded the machine. Nothing changed. When I turned the hand wheel, it would turn smoothly for a second before it started to resist. It took a lot of effort to crank it forward even just once.

I checked for jams and checked the belt. Everything looked fine to me, but I am also a novice with no machine maintenance experience. I have no idea what's going on and the nearest repair shop is a real hike. What to do?