What Causes Irregular Periods And Loose Motion Along With Cramps?

Am always going through in a 35 day cycle.my last period was 21st of may. And we are trying for a baby since the day 4 from my period.its been 20 days now.. is there any chance of getting pregnant? i have been going through a mild headache over back of my head for the last two days and i feel like a kind of loose motion stomach cramps and lower left abdomen is hurting a bit.. doctor pls do answer me in detail according to my query.