Sperm can live inside the body for several days. The most I heard was about 5-7. There is definitely a chance but you have better chances having sex during the week you're supposed to ovulate. And make it every other day to keep sperm count up. Good luck to you and KEEP US POSTED!
I think its possible. Depends in how long ur cycles are & when u ovulated. The bleeding could have been implantation bleeding.
If your period was due on the 21st, sex on the 13-15 might have been too late in your cycle.