Hi Brianna,
I do not believe you would have demonic anxiety. Demonic anxiety would involve you being posessed by a demon and them being the source of your anxiety. I did a quick search on google and I caould not find any information about this being a disorder.
I found a lot about demon possession but that is not what you are experiencing.
Anyone can have anxiety for a large variety of reasons. None of these reasons have to be fully understood. Sometimems I feel anxious and I do not quite understand why.
It would be best for you to talk to your therapist/counselor about this. In regards to the demonic aspect, could you speak with a religious leader from your church for guidance?
It is always best when you hear something from someone to see what you can find out from people around you about what you are being told in regards to how accurate the information is.
I hope this helps you some and you can
PM me if you would like to talk farther.
Take care.