I had sex and 3 days later I got my period, it only lasted about a day and a half - then it was only spotting for the next 4 days everyday was lighter then the day before, I wouldn't think anything of but since I can remember mine have always been heavy and painful, I have read that it may be a sign of pregnancy, I also read that if you have more trips to the restroom that's a sign too, its still to soon to take a test, I still don't know what this could mean, could you give me your opinion

Yes, both are signs of possible pregnancy. However, stressing out about it is silly, because there's nothing that can be done right now. If you are really worried, head to the OB.