When is your expected period? Are your periods regular? You can get an urine pregnancy test done.But pregnancy will not have these symptoms usually.I suspect you are probably having a Pre menstrual syndrome.A woman with PMS will have monthly cycles of symptoms in mood, behavior, and/or physical functioning.Headache, heart pounding, fatigue, dizziness, weight gain, bloating, breast swelling and tenderness, constipation or diarrhea are the ones usually assosciated.You can avoid foods high in salt (sodium), avoid candy, soda,caeffine,and other sugary foods especially in the week before your period. Taking calcium and magnesium supplements is said to be help ful to some.Regular aerobic exercise and relaxation techniques can help to relieve many of the mood symptoms found with PMS. Muscle relaxation techniques and massage therapy may help.Anti inflammatory drugs are used to treat PMS.In case you still have no relief you might need an examination by an gynaecologist