Suggest Treatment For Cramps And Red Spotting After Having Tubes Tied

Have had tubesvtied for over 3 yrs. Period came like it was supposed to at the end of the month it comes between 23 and 26. It came March 23 and was completely normal. It s April 7th had sex 4 days ago and have had light pink to light red spotting for 3 days now. I have a some minor cramping that comes and goes. What could b causing this