How Can Irregular, Scanty And Unusual Menstruation Be Treated?

Im having irregular menstruation. Me and my husband is trying to have baby. Recently, the past 2 months my period came monthly. Now is third month that and it came on time but its seems different from my previous periods. First day was brownish,then second day until 4th day,it was very light flow. I can even use a pantyliner for the third and fourth day. What are the causes of having very light flow of period? Is it possible that i could be pregnant?