What Causes Irregular Periods?

Hi, may I answer your health queries right now ? Please type your query here... hi I have had trouble past year with periods and my cycle. However I seen a period two weeks ago which was very very light (unusual as i used to be heavy) and it lasted 12days. and now a week later im seeing a light pink discharge should i be worried? could it be an infectio. My motherinlaw told me not to worry