Hey n2L I had those same symptoms on 1000mg metformin. It settled down after a week or so.

I believe the metformin helped shorten my cycles a bit, each month for 4 months I would ovulate after less and less time until I was averaging ovulation at around CD 20. I'm not sure about egg quality but I don't think this was or is my issue as I'm still young.

Good luck babes!!