Hi,
Welcome to the forum. I am really glad to help you out. The possibility of pregnancy needs to be ruled out. To confirm the status of pregnancy, I would suggest you to get your serum HCG levels estimated since this is more specific than urine for pregnancy tests. The HCG (it is a hormone) levels rise only in pregnancy and its presence will confirm the status of your pregnancy. If it is negative, then other causes of delayed periods needs to be looked into.
It can happen because of hormonal imbalance, increased stress, eating disorder, increased smoking, alcohol or caffeine use and medical conditions like PCOS, fibroid, polyps and endometriosis. Please do consult a gynecologist for the same. I sincerely hope that helps. Take care.