What is this? Please help

Dani

Hi guys I’m on the nuvaring as my contraception, been on it since December and I’ve been having regular sex with my boyfriend. I recently started experiencing cramping and stomach/back pain alongside heavy bleeding. I thought my ring had fallen out or it was a period but then this came out of me. Please anybody do you have any answers. I did a test and it came back invalid and then negative after I’d passed this. Please help.