Questions on my pregnant guppy fish!!?

SO I was wondering is it normal for my pregnant guppy fish to always be rubbing on the rocks and fake plants all the time like she is itchy and also before they give birth do guppy fish get aggressive and territorial because mine normally is not and she is acting really strange also what should i do when she is gonna give birth should I put her in a separate tank or a breeding net/box im confused on which one is better and don't want to traumatize my guppy fish. There are 2 other fish in the tank so I don't want them eating her fry. Also she has given birth to 6 fry already and how come I never see it do they prefer to give birth at night?? Is there a easy way to know by her actions when she is gonna give birth. She keeps attacking the other male fish I have in the tank its not a guppy and I think it is eating her babies when she gives birth! Why is my pregnant guppy acting so strange all of a sudden?