My stepmom won't stop going through my things she thinks that i steal everything.what do i do????

Ask yourself, does she have a logical reason for believing that you steal everything? Have you stole from her or another family member before? Have you stole from a store and she found out about it? If so then you cant blame her much for that. If not, just continue on letting her look stupid when she searches for things she will never find....she will eventually give up if she has nothing to really work off of :)