Stopping birth control due to insurance issue...advice?

Meghan
My new insurance has a 60 day waiting period and I found too late. I have been on Nuvaring but can't afford it til the new insurance kicks in March 1st. I finish nursing school in June. My husband and I are really wanting to try natural family planning until shortly after I graduate. Anybody have advice, tips, tricks, etc to use along with this app? I have never done this type of birth control and am feeling a little overwhelmed. I got pregnant with my daughter after being late taking the pill for 4 days in a row and don't want to get pregnant ahead of schedule...