My diabetes nurse has said that there is a chance i could have the virus and not even know about it, with my type 1 diabetes. is this correct?

Depends on the virus: Yes. We get lots of viruses. Usually, the only ones we know about are the ones that cause us symptoms. Sometimes we find out we had gotten a virus because something shows up on a lab test. Basically, every person has gotten viruses they don't know about and don't have to worry about. That's how life works. All animal species live with a variety of viruses. Only worry when doctors say, "Worry."