periods longer than usual

Hi ladies

I have had this wierd thing for the first time in my life and need your sincere advise please.
I am 26+ years of age, marriied for a year and a half, average sexual activity (with protection). I usually have regular 5 day-periods every month. THis time however, i was 5 days late to begin and bleeding is still on, although its the 7th day. There is no pain/no heavy bleeding but i am very worried. THe only changes recently that i can think of, are an increase in physical activity as i was learning swimming last month and work-stress is like always.

Ladies, i am planning to visit the doc in another day/two if this continues but would really appreciate if you could pour in your suggestions/experiences. I am really troubled, worried and irritated with this

Thanks very much
Charu..