Im not sure please help =/?

every month my period comes on the 8th and than again around the 16th. its weird but thats how it works lol. but i had about a week and a half before my period should have started so i dont know if i was ovulation or ne thing. there was no protection and he did not pull out. please dont give me crap though i have been dating this guy for 5 years and we want a baby. but ne ways i am 3 days late. but i dont know if i should take a test cause im thinking it might still come on teh 16th. and i am really tired of beign dissapointed with a negative result. i dont have ne signs of my period starting but my kinda hurt and i feel kinda exhausted. oh and i have alot of discharge. (more than norman) but thats it. so what do u think. should i take it soon or should i wait and see if i get my period on the 16th? im so tired of negative results =(