You should see that the female goldfish appears fatter than usual due to the eggs she is carrying. The male will have white spots on his front fins and gill covers and will pay the female a lot of attention chasing her around the tank or pond.
The thing is you won't know- that's why its so important to do plenty of research into breeding goldfish before you breed them. There are many wonderful books and pieces of information available that you could read. I'd suggest going to local petstores or the library and reading the books they have to offer about goldfish- most books will usually include a section on how to breed goldfish.
they puke
They will be really fat.
Goldfish don't get pregnant. They lay eggs (ova). If it is springtime in your part of the world then female goldfish could well have their ovaries full of eggs and be ready to spawn. If they do not spawn, the eggs will be reabsorbed by the body.
It is physically impossible for a goldfish to burst on their own. It may be a female who is about to lay some eggs.
Goldfish do lay eggs. The eggs will attach to something in the tank or bowl until they hatch.
when you get it a mate.
Your goldfish isn't pregnant, its just becoming full of unfertilized eggs. Truthfully you shouldn't worry about it, unless you have a male around who is ready to spawn, the female will just lay her unfertilized eggs and then eat them.
Yes. Laying eggs is how they reproduce.
Goldfish are egg layers
Yes.
yes
Yes.