Meaning of “upset” - Learner’s Dictionary

upset

verb [ T ] uk us /ʌpˈset/ (present participle upsetting, past tense and past participle upset)
WORRY

B2 to make someone feel unhappy or worried:

The phone call had clearly upset her.
SPOIL

to cause problems for something:

If I arrived later, would that upset your plans?
upset sb's stomach

to make someone feel sick in the stomach

(Definition of “upset verb” from the Cambridge Learner’s Dictionary © Cambridge University Press)