Also, thinking some more on this. Does your doctor or pharmacist know you are taking aspirin? It can potentially interact with the Apo-clopidogrel.
Backaches and traces of blood in the urine...
Have they tested for kidney infection? Do you have any burning when you urinate or a frequent urge? Do you see any blood when you wipe? If you have any of these, you'll need antibioitics.
Follow up the lab results with your doctor, but in the meantime, you could try cranberry juice or cranberry pills and be sure to drink plenty of water. This will not cure things if it is a kidney infection or a urinary tract infection (You will still need antibiotics), but it is a habit that is supposed to help prevent any future infections if kept up.