Singer lube is getting harder to find. Jenny has it at Sew Classic, and most shops should be able to order it, but you may have to buy 6 tubes at a time (minimum order for most dealers, here in Canada at least, so YMMV)
This is what Singer recommends for the gears. It's thicker, stays in place, and doesn't "liquify" as fast when it gets warm, hence why we also use it in the Singer motors that require it.
That said, I've heard of people using all sorts of grease on the gears (the motor must have the Singer lube, so it doesn't hurt to buy it and use it for the gears too) - TriFlow's grease product, Vaseline, axle grease, etc.
And no, you didn't ruin your machine.
You just aren't finished the maintenance.