Is this normal??

My period started Jan.8 and ended Jan.15, on Jan.18 me and my partner had unprotected sex and everything was fine after that (withdrawal method). On Jan.21 when i went to the bathroom i felt as if i had gotten my period but i did. It was like a gooey, bright red blood type of thing. (Take a look at the picture). That was the only time it happened. I wanted to know if thats normal, this is the first time it has ever happened. Has anyone experienced something similar?