I've been on Tri-Sprintec for 2 years. I just switched to a lower dose, Loestrin24FE, and finished my first pack of it on Tuesday (there are 24 active pills and 4 iron supplement pills. I didn't take the iron supplements because I didn't want them to interfere with my vitamins). I've never missed a period, but I missed it this month! I began taking my next pack today (Sunday) anyways. I took two home pregnancy tests (one on Friday, one today), both of which were negative. I have a lot of questions: Is it common to miss a period when one switches to a different oral contraceptive? Did I do the correct thing by beginning my next pack today? Do I need a back-up method of birth control? Is there any chance that I'm pregnant? With my last active pill ending on Tuesday, when can I expect my period to start?
Thanks for any help!