Hi Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concern... As you are sexually active & haven t had a period for 40 days, you should get your self checked for pregnancy. Sometimes you could get pregnant through a intercourse with protection too. This occurs when you insert penis before ejaculation or even after ejaculation without condom or during condom break which you might not have noticed. There could be other reasons that may be responsible for delayed periods as follow 1 Ovarian problem like poly cystic ovary disease (PCOS) could be the reason as you have history of irregular periods 2. Overexercising or excessive exercise schedule 3. excessive weight gain or weight loss 4. Hormonal disturbance 5. Excessive stress can cause delayed period too by upsetting normal hormonal imbalance If problem persist, visit a gynaecologist Hope this information helps