I am 41y/o, and in the 5th week of my pregnancy according to internet calculation. Through out this pregnancy period, I have mild cramps often and on, heartburn and constipation. Yesterday, I did mild physical exercise and had an intensive intercourse. At night, I had a moderate cramps and around 9am, I started having mild bleeding (light red color) and cramping. I was thinking that it might be trauma from sex. Am having bed rest. Please, do you have an idea of what this might mean?