It doesn’t happen immediately after sex. Sometimes like the following week. I’ve been on Nexplanon for over a year and this is usually a common occurrence for me. I let my boyfriend ejaculate inside me, and about a week later I am having period-like symptoms. Sometimes full on bleeding, other times my body is reacting as if it’s the tail end of a period with dry-brown colored blood. Just wondering if this is a natural occurrence with my body trying to interfere with a possible pregnancy?