How big are those scratches, is it possible that you scratch yourself in sleep?
The rest sounds rather scary and I don't have any experience with demons, it would be better if it is just a ghost ( I am serious), since you could tell them to go away( I heard so). A demon on the other hand, is way more dangerous.
When I understood you right, then the demon followed you. Normally, that is not possible. So my question is: Is there something that you took with you from the apartment?
BanglaBoy96
yikes! that is freaky! I'd love to help you out but I can't think of a way other than a religious way which actually works cos my Aunt had a problem similar to it.
But I doubt you're the same religion :P