Theft is not big deal

Theft is not a 重罪 from the law prospective. It depends on whether you possessed weapon when you conmmited it. It could bring you many charges. And it depends on the you situation, quantity of the property you took, what kind of property you took and where you took. It will bring a lot of issues. Since you are Chinese they will treat you in a little bit different way - more serious way.

Anyhow, this is not a big deal for you. You do not have to die.

Find a lawyer and ask him to help you. You may need several hundreds to several thousands CAD if you are in Canada. I do not know how much you will pay in US.