advice pls.

maan
dont know whats happening im 6 days late... my usual cycle is 30-37 days but this time im on my 40 days cycle. i just had one sex this dec. and i believed my man didnt cum inside... what makes my period late? im overthinkin here.. i cant sleep well everyday thinkin about this. i've search some signs of pregnancy but all was not match to me except the late period. havent takeb pt .im waiting my bf to come coz he is on vacation. and im scared. im working abroad. so this will affect my work if i found myself preg. pls. help me.. any good advice to make me calm?