Dewormer my 17 month pitbull an he stop eating I don't know what to do .idon't have no money so help me

We need more background information before we can give accurate advice or suggestions.

Is he drinking water and urinating? Is he throwing up?

How long ago did you de-worm him? What type of de-wormer did you use? What dosage and how was it given? Has he gone to the bathroom? Has he had any other issues like changes in his behavior?