What Causes Yellow Vaginal Discharge And Abdominal Pain?

I am aged 32, with 2 kids and trying to get another pregnancy. i had my pap test and colposcopia in june 2010 and all was well. This is the second month that at mid cycle, i have light blood flow for two days. This month i had my cycle onthe 14th. Have had sex with my partner quite a number of times this month. Yesterday i had light but prolonged yellowish and watery discharge followed by a light pain inthe abdomen. Later in the evening and at night, i had light spotting. Is this normal?