I take birth control and i missed it one day 6 days later me and my boyfriend had sex and he said he might have cam in me a little since i missed a day 6 days ago we decided i should take plan B just in case. On my birth control it's saying that i should have started my period 4 days ago, but i start a day later or 2 after it says i should. but never 4 days over should i be worried ?