Como dizer "pesadelo/fantasma" em inglês

Bugbear = (fig) pesadelo, fantasma (In a modern context, the term bugbear serves as a metaphor for something which is annoying or irritating) Ref. Wikipedia

Exemplos:

1 - Maths is my bugbear = a matemática é o meu pesadelo
2 - Inflation is the government’s chief bugbear = a inflação é o grande pesadelo (fantasma) do governo
3 - "Germany was always a bugbear for France" (an object of dread or apprehension) = A Alemanha foi sempre um pesadelo para a França. Thefreedictionary
4- For many islanders this will be welcome news. The suspicion that some traders contrive to keep food prices high is a bugbear that will resonate across both Jersey and Guernsey. Ref. thisisguernsey
5- Rupee depreciation a major bugbear for India companies. Ref. deccanherald