30 Day Shred

Before this weekend just gone I had nearlly finished level 1, I had few days off (boyfriends birthday plans and then being poorly) and I'm going to start again tonight, should I go back to level one? Or start at level 2? Also I bumped my knee and now theres a really nast bruise which is killing, is level 2 as hard on your knees as level 1? Any help would be appreciated xx