I believe Susan has already answered your question on another thread you started last week. If you have gotten a period after you had unprotected sex, then you are not pregnant. Sometimes periods come lighter--sometimes they come heavier. Usually if it's lighter this month, then next time it may be heavier. If you want to ease your mind, you can take a home pregnancy test.
In order to answer all new questions adequately, we as that same or similar content remains in the same original post and not in a new one-- thanks :)