Starting Metformin. Is it enough?

Maggie • 30- Happily Married. Diagnosed with PCOS at age 19.
So after two rounds of Clomid where I did ovulate but didn't conceive my doctor prescribed metformin. However, he only prescribed 250mg per day. Obviously, I'm not a doctor but it seems really low compared to what others are taking. I'm wondering if it's even enough to do anything. If anyone has experience with metformin I would love your thoughts on this. Thank you!