What is the difference

Shari

What is the difference between Metformin and metformin ER I am on metformin ER for weight loss I don’t see how it is true bu I been on it for 3 days and the scale said I lost 7lbs in 3 days I also think my doctor thinks I’m pcos and he won’t come out and tell me I just don’t see how when I have 6 kids one with my husband and he wants another one so we been trying for a year my cycles went from 28 days to 37 days