Thanks for the replies,
This is what happened and the only explanation that i can come up with. The FB account was just coincidence.
I recieved a text message from and i usually don't reply straight away anyway. I was busy as well I had about a 30 minute drive to where i was going and on the way i recieved another text. the phone was basically on silent and the music was very loud.
I arrived at my destination and done a u turn parking in a small lay-by on a country road. stopped the car grabbed the phone to reply. but it had a 1 on the messages tile I have another message. read the message and replied went to reply to the first message and jumped out of my skin as it had been answered about 2 minutes earlier.
I can only think that i must have typed the message before i left and had a senior moment and not sent it picking up the phone somehow i sent it.
The only problem i have with that is that when i first looked at the time it was sent it was sent as i was driving. Now it shows it was sent at the same time as my other reply. I'm 100% sure as i text someone and told them.