Can't stop, won't quit

Hello everyone! I am on week 4 day2 and absolutely love this app! I can't believe I am actually doing it. Im 46 years old! I've got my entire family doing it with me. My question is how can I do over again the days I've done already w out loosing my progress. I'm afraid I'll erase everything. In addition to being afraid I won't be able to do week 5 w out doing week 4 forever lol