Strange cycles after Egg collection...

Ni

Had egg collection on 25th of November and period about 10 days later. I’m now on CD27 and no ovulation yet. I’ve always been regular 31 day cycles so this has thrown me somewhat especially as we were planning a non medicated Jan FET and at the moment looks like it’ll be delayed until I know what’s going on. Did anyone else have problems with cycles after EC? I only stunned for 13 days and didn’t suffer OHSS...