Help! What have I made? Is it safe to eat?
It sounds like you may have made paneer. Rubbing undiluted lemon juice and vinegar on the pot, then drying it without rinsing, would leave a significant amount of acid dried on the surface. That acid dissolved into the milk, curdling it.

If so, it's safe to eat. Generally paneer is rinsed after curdling to remove the acidic taste.