Sounds like something you should seriously ask your doctor.

Is it possible your tap water is low quality? An interesting experiment would be to boil some water for 5 min to kill any bacteria. Then let it cool, and then pour it in a container and pop in the fridge. Then try drinking that in the morning and see if it resolves your issue.

With the coffe it’s already getting boiled for a short time, with the apple juice and oj, you might not be drinking enough water for it to affect you, and it’s getting diluted.

Isn’t Ubuntu a UK company?