What Causes Jelly Like Discharge In Periods?

Hello, I am a 22yrs old and I didn t have my menstrual cycle for 2 months...my menstruals are usually every other month but I haven t had it since Feb. I took a home pregnancy test but it showed negative. I did have some symptoms of pregnancy and my stomach looks to be growing, but yesterday I had gotten my menstrual out of the blue and after a couple hours I was having cramps in my abdomen and heavy bleeding started, I went to the restroom and when done I had seen a discharge, It is almost like a jell like texture. I had touched it to see what it was and it was a little sticky, this had me a little scared because this is the first time it has happened. And I do not have children, what could this be? I m just a little frightened because I was trying to look up what this could be, please let me know what this could be or might be. Thanks for your time.