Took Naproxen For Four Days For Back Pain. Started With

Took naproxen for four days for back pain. Started with chronic diarrhoea within three days, doctor took me off these and tried me with codeine saying these would have the opposite effect endless to say it didn't. Took me off all my med except gabapentin which I have been taking for three years. Eight weeks on I still have chronic diarrhoea going between ten and twenty times a day. Doctor gave me loperamide to stop it . Been taking a week now still has not made any difference cannot even keep a drink inside within five minutes I am rushing to the logo also the noises from my stomach sounds horrendous. Please can you help