Krikkit, I'm sorry to hear about the bfn. I just did back-to-back fresh cycles because we had no embies frozen from IVF#2. I was told to come back at 7DPO of the cycle after IVF#2 to confirm I had O'd and then could start the synarel again that day. 7DPO ended up being something like CD33 because the IVF in the previous cycle delayed O by a week (happened again this cycle after IVF#3).