Spotting and cramping two weeks after period

Patient: My girlfriend had her period two weeks ago, and she is currently on birth control and we use condoms everytime we have sex. However, in these two weeks we only had sex with a condom yesterday morning. Today, she is experiencing cramps and spotting, which is very unusual for her. What could be the possible symptoms of this? She has been under increased stress lately.

Symptoms: Spotting in vagina, cramps in abdomen