A few years ago, well before I started SF, I won a 6 month gym membership. The first time I went, I hopped on the Gravitron (assisted pull-up machine) and did a few sets.
I was sore FOR WEEKS! I charlie-horsed my biceps for crying out loud. It was brutal. So I can sympathise.
I would keep up with Level 1, and just go at a slower pace for a few weeks and work your way up. DON'T QUIT!