Metformin Trying to conceive

My doctor started me on metformin this week i haven’t started taking it yet because i have read a lot of negative side effects. Has anyone else taken this and lose weight get regular cycle and then become pregnant with it ? I’m suppose to take this for a couple of months need to lose 25lbs then start clomid afterwards. I’m suppose to take 500mg twice a day but I’ve read it can cause dementia down the road. I need answers before taking it I’m nervous 🥺