Embarrassing but need answers ..

Okay so yesterday I had this blob come out of me and  I wanna know if this has happened to anyone or any advice as do what this could be ... (I'll attach a picture so you can have a better idea) 
Anyways at the moment I'm not sexually active and I have no stds as I've been tested a bit ago and haven't been with anyone . So just wondering what this could be ... 
Thank you xo