Things around here are about to get crazy

My roommate has been using a lot of my things lately.
Like one time I came home and she was trying on my shoes, she uses my deoderant (which is repulsive on so many levels), shes been stealing my water bottles, she took my belt on vacation with her without even asking, she finished off an over-half full pack of oreos, etc etc etc.
And let me stress one more times we are not friends! So it’s not okay for her to do this stuff. If we were friends it might be a different story. 

Then today, which has been a not so good day, I come home and she has used alll my crystal light. There are water bottles on her side of the room with the crystal light in them. So I text her and confront her. Of course she denies it. But this shit ends here.
I am beyond sick of her thinking she can do whatever she wants. This is my stuff not hers.