Ortho Tri-Cyclen Lo to Sronyx

My girlfriend has been on Ortho Tri-Cyclen Lo for about 4 years with no side effects. Yesterday I went and picked up her 3 month supply of pills for her, and didn't realize until this morning that they didn't give me the OTC-Lo but gave me Sronyx instead. They told me nothing about this, and she had never discussed switching with her doctor. Obviously it's the weekend and we can't get in touch with the doctor, and she is due to start her new pack tomorrow. I have researched both drugs, and while there are some similarities, there are also some big differences (monophasic v. multiphasic). Hopefully it's clear to you by now that I know very little about these drugs, but I was hoping to hear from a doctor regarding what to do. Perhaps waiting until monday and consulting with her doctor would be the best bet, but if they're fairly interchangable she'd obviously rather start the new pack tomorrow. Any insight that medical professionals can lend is greatly appreciated. Thanks in advance.
Nick & Nicole