TTC irregular periods

Sophie

We have been TTC for coming upto 9months now. I always thought my period was relatively regular but since being so obsessed over not being pregnant🤦🏻‍♀️ i have been looking into it and it seems to range from 27-31days and I ovulate between day12 - day18 🤷🏻‍♀️

Does anyone know why this might be? Any help is greatly appreciated.

Thank you! 🥰