Hi there 1st you need to find out if you are pregnant and you do need to calm down as stress can delay your period and if you are pregnant it is not good on a pregnancy. You should pick up one or two home pregnancy tests, the best time to take them is in the morning when you first wake up and believe me, they are not always 100% accurate so then after you try your 2nd test and no period and not all women have symptoms, heck, I had 3 periods with my pregnancies anyways, then you go to the dr and allow him to test you and hopefully he will do a blood test as that is more accurate.
Good luck!
Keep us posted!