Metsmall (metformin) is highly unlikely to cause erectile difficulties; in fact, keeping your diabetes well-controlled actually helps protect your long-term sexual health. Because this change happened suddenly over just one week, it is much more likely related to temporary factors like stress, anxiety, tiredness, or lifestyle changes rather than your medication or diabetes itself. I highly recommend discussing this openly with your doctor. They can help reassure you, identify the exact cause, and guide you toward a simple solution.