You really must go see a doctor, ASAP. WARNING: If you continue as you are doing, your life will be very short and your demise will be horrible.
The acetaminophen that comes with the meds is toxic to your liver. The maximum daily dosage for a healthy person is 4 grams / day. You are taking almost twice that. If you are malnourished and not getting enough calories, the meds are incredibly toxic. Proper diet is necessary to replenish what is called the cytochrome P-450 system. Without a sufficient diet, the liver cannot process the acetaminophen and liver cells die from the toxic metabolites.
Your stomach may be hurting because your liver may be damaged. The liver can regenerate if you act in time.
Don't delay. If you are having serious liver problems, time is of the essence.
Please choose LIFE. After you go, please let us know how you are doing.