A negative
pregnancy test 5 days after your encounter followed by a positive one at day 10, together with breast tenderness, milky white discharge and mild cramping, is a classic and reassuring pattern for an early pregnancy, since hCG often isn't detectable until a few days after implantation. Your cycle timing and symptoms line up well with this.
Next Steps
Start a prenatal
vitamin with folic acid if you haven't already, and book a blood
beta hCG test plus an early dating scan with your obstetrician over the next couple of weeks. That scan also rules out miscarriage and ectopic pregnancy, the standard first check for anyone this early on.
Health Tips
Go in sooner if you develop vaginal bleeding, sharp one-sided pain, or cramping that doesn't ease, since those need prompt review.