Passed a large blob at 15 weeks

This is a TMI thing but need some insight. Yesterday, I passed a massive jelly-looking brownish blob the size of a silver dollar. Every so often when I go to the bathroom after that, I'll see this clear egg white like discharge tinged with yellow, pink, or brown. No cramping. What's weirder is I was on vacation and had to cut it short bc I was getting severe lower back pain only going down the left leg. I have a herniated disc and was sleeping on a not-so-comfortable bed so attributed it to bad sciatica pain. Well after that big clot/blob thing passed, my back pain drastically decreased. Still there, but don't have to walk with a cane now. OB is just as confused as I am. They are thinking it was the mucus plug or a clot that my body decided to release all at once. Anyone have something similar happen?