Caroline,
If you use the link I provided, in my first post you should get a pretty good idea of what it looks like under yours. Mine is a 2011 Cougar.
If it is your black tank, I would continue to camp and just not use it. I might take some time to flush copious amounts of fresh water through the toilet to try and flush as much as possible through the drain and out whatever leak you might have thereby flushing out the underbelly. Once done and the area cleaned up, the smell should dissipate.
Once the holiday weekend is over then I would contact your extended service provider and advise them of the problem then find the most trusted RV repair facility you can and bring the trailer to them.
Based on my work and what I've discovered along the way, be prepared to be without the trailer for some weeks as this is not an easy job but, as I proved, it is certainly repairable.
Best of Luck!