Welcome to board Gracie,
Brendaks has some good advice. You didn't mention any history of lower back problems, but try putting heat on and take some kind of anti-inflammatory for a couple of days, if you can take them.
Does the pain in your lower area radiate around to the front? Be sure you move real slow and take the necessary time you need to see how this goes. I would say if your symptoms don't improve, or worsen, so that you can't bear to move in a couple of days, get to that dr sooner if you can. Hope you have supports in the bathroom to left yourself up and down so no further accidents from this.
Hope others can post here with some help as to that cracking noise,
choc