What Does Swollen Lymph Node Near The Groin During Periods Mean?

Hi,

I started my period last Friday, Feb. 4th. It started normal and was slow at first. Saturday I woke with much heavier bleeding but still in the normal range but with a swollen lymph node on the right side of my groin. I do not have any other lymph nodes that are swollen. There is no redness, no fever and I am not cramping. It was very tender on Saturday to touch but does seem better today, although it is still swollen. I am 39 years old and in good health and weight. Cancer does not run in my family. I have three kids who have all had the common cold recently and one is still currently fighting it. Do you think I should be concerned or could this just be due to my period and maybe a virus?