Can I still amend and file injured spouse? If I didn't have an income, will amending matter? I live in the state of Mississippi, if that matters.

If you have no income, an injured spouse claim cannot be used.  The  point of an injured spouse form is for that spouse to receive the portion of the tax refund due to them based on their own income.  If you have no income yourself, then none of the refund would be due to you.