Iam male age 48. after not having my metformin for 5 days,got my prescription today and took my 1. I am feeling very strange, headache, not normal at all not just physically but my head doesn't feel normal. Is this common due to stopping suddenly and starting back on my normal dose? i also didn't really eat before taking my pill. I will really appreciate your answers and information as much as possible. Thanks for your time!