My question involves criminal law for the state of: North Carolina

Alright, so yesterday I was in a department store at my local mall, and made a really bad decsion to steal a $400 handbag for my girlfriend. After I left the store this girl can up to me with a badge and said she was store security, and wanted the bag back. I told her she has no right to stop me because she is not a cop, she wanted me to come with her back to the office to discuss the bag. I told her no and started to walk by her and she went to grab my arm. She can't touch me thats illeagal, so I defended my self by punching her in the forehead and she feel down, at this time two store people came running out and grabbed me, she put me in handcuffs whitch she can't do because she is not police. I kept telling her I was going to sue the store because she is kidnapping me. When we got back to the office she started asking me questions but never read me my rights, so nothing I said can be used againist me, right? They called the police and they came and arrested my for shopifting and assault, but I was just defending myself. Can anyone give some advice on what I should do because they had no right to do what they did, store security is not the police. If the police stopped me I would cooperated. I want to sue this company for kidnapping, assault, and for humilitating me in the middle of the mall.

P.S.
I am a really good person, and have never been in trouble before with the police. This is really fustrating because I was charged with two things but was already out of the store.