There are many causes of bad odour from the mouth like gum disease, halitosis, tooth decay, abscess etc. Poorly fitting dental appliances, yeast infections of the mouth, and dental caries are few other common causes. Respiratory tract infections such as pneumonia or bronchitis, chronic sinus infections, postnasal drip, diabetes, acid reflux and liver or kidney problems are few other causes of bad breath. Drink plenty of water and brush your teeth twice a day and floss your teeth at least once a day. See a dentist. He will determine the cause of your bad odour.If the cause is dental he will advise treatment accordingly if not then you may need evaluation for above mentioned conditions. Get yourself treated. I hope it helps.
Take care and regards!
Thank you very much, most likely it was acid reflux because am now fine after taking lots of water.