confused with ovulation

my first kiddo was a surprise that beat birth control haha. this time my husband and I are trying. but I don't understand timing exactly. Okay so for example... We have sex through out the ovulation time and then my period is supposed to start in two weeks. Will that period still start even if I am pregnant? or will it just be late but need to be a month late before I can actually test. I see boxes saying "test up to 5 days before your missed period" but that would be less than 14 days past conception. I recently was 1 week late. I had nausea, heart burn, and my boobs were sore. I took 3 years, all negative, and I thought oh it must just be too soon. then a week later there's blood. :( so I am confused. do I just have to go through that repeatedly for a couple months And then test of there still isn't blood?