What caused this heavy discharge soaked through my jeans?

Extra discharge can be caused by a lot of different things!

If this happened 1-8 days after the last day of your period, you could just be ovulating. Ovulation is the point in your 28 day cycle when an egg is released for fertilization.

However since it smelled a bit, it's a little suspicious. Two more common causes would be vaginitis and yeast infections. These are most often accompanied by smell, extreme itching, and a burning sensation when you pee.

The third possibility is that it is caused by an STI. If you have ever had sex (even with a condom), and haven't gotten tested, there is a chance that you may have an STI. One common misconception about them is that the symptoms are extremely obvious. This couldn't be further from the truth. In fact, many, many cases go untreated because they are asymptomatic or have very few symptoms.

To be safe, you should go see you gynecologist and get tested.for vaginitis, a yeast infection, and (if you are not a virgin) STis.

Good luck!

Sounds like an infection, please see a doctor, vaginitis is not nessecarily from sexual contact at all.