What Causes Nausea, Tiredness, Abdominal Cramps And Irregular Periods?

"Hi doctor, I'm 27yrs old and married. My periods cycle were usually 29-30 days.But I have been trying to concieve for the past three months and last month my cycle lasted only 25days and this month , when it crossed 30 days, i was expecting to be pregnant . i had slight nausea , tiredness and abdominal cramps for 10 days now. But I was bleeding today (i.e, 34th day since LMP,) almost like my period and I am very upset.

Could I be pregnant or What could be the reason for this irregular period ?

Please reply... Annie Jinu