What Causes Dizziness After Drinking Coffee?

Over the past few weeks I ve noticed that I sometimes feel lightheaded during the day, which has never happened before. The feeling can last for a few moments or, at least today, for a few minutes. 1. At what point should I become concerned? 2. Is it possibly linked to something I consume? I m not sure but I think I experience this several hours after drinking coffee from a specialty shop that I rarely use.