I hope you still have a few wits left by now! Is that the right bobbin? Have you pulled it out to make sure the thread path is clear? Is the needle thread threaded correctly? I usually pull everything out and start from scratch when these crappy things happen. Good luck!
you also might search for treadle sewing machine and see if folks have any tips. We had a treadle machine when I was a kid-very fun, but no reverse, only forward as fast as you tread! Be sure and put in a new needle too.