I lived with a married girl, and she asked me to leave and now I can't get my things that I brought over

So in essence you purchased items with your own money to use for this joint relationship but she is married? Is she separated or in the process of getting divorced?

The items you purchased -- were they purchased as a gift for her or were they purchased before you met her and simply something you needed to move with you?

If you have receipts, etc, and she will not return them, you may be able to sue for the whole amount (original purchase price) but it may be discounted for use/if it is used. You can also sue for their return, but if she is not returning them and not going to respond, that may be tough to do.