I took Levlen ED, the contraception pill, for 8 months and then my doctor changed me onto Yaz, a different brand, because I was experiencing side effects. However, Yaz is a lot more expensive and when I finished the pack I was unable to afford a new one so after the sugar pill week I started taking Levlen ED again. Mid-month, after about two weeks of Levlen, my funds improved and I was able to purchase Yaz. I started the Yaz active pills immediately without finishing the Levlen. Is this wrong? Is it okay as long as I use back up contraception for 7 days? Thanks.