Ive had my period now for 2 weeks straight. Im 17 years old and am sexually active but im on Nuva ring. My period is light but has brown clotting and tissue in it. Could my nuva ring have caused a miscarriage? Ive also had lower abdominal pain, but it sometimes moves to upper abdominal pain aswell. Im taking nexium for stomach issues. HELP! what could this be?