If I have unprotected the day before my expected period, how long should I wait before testing?

I was told pregnancy tests were extremely accurate from the day of your missed period on. But because I had the day before my expected period and because it can take about 6-7 days after to become pregnant and then several more days before the pregnancy hormone can be detected, does it mean that a test taken the day after my expected period (2 days after I had ) could be too soon to be accurate? Another question: would getting my period in this case still mean I wasn't pregnant, or would it be too soon to tell because I had so close to the time I was supposed to get it? A rephrase: do you still skip your period when pregnant no matter when you have , or can you have it so close to your period that you would not skip your upcoming period but instead the next period? Had to cover all the bases...and please don't say go see a doctor. Obviously I will do that if I do not get my period soon. I would just like some peace of mind before I go to sleep.