I NEED HELP

First off. I AM A NOOB. next, i have a problem. OK. i was texting my gf a question. THEN i get some wierd ass response

from her like shes talking in the 3rd person. it is very very detailed (about our conversation). I was mad and said "WHO

IS THIS" (I thought one of her friends took her phone) When i went to look at the message, it was GONE. gone from

my inbox totally. No more creepy message, instead, ANOTHER response from her (to the same question) only THIS

TIME its a regular sounding message from her. her response from the "who is this" was no more than a confused

"What??" So i go online to view the text logs- no record of it being received by my phone. Could someone have

hacked it? its just very creepy due to the way the text was completely in context of what we were talking about.

Im just kinda paranoid right now.

please help,
Phunnyman