AC turns cold then hot - 2003 Deville

Hey CF! I have a 2003 Cadillac Deville that recently been having some issues it started last week where I would turn my AC on it will give me fresh cold air for a minute then it will start throwing warm muggy air and this happens every time cold then hot cold then hot ... anybody knows what the issue is? I haven't got time to go to a shop yet and CF has ALWAYS helped me out if anybody knows what the issue is or how to fix it please let me know thanks CF!