Currency is EUR, but est. revenue is Pound

Hi,

I couldn't find any information about this, so I'm hoping you can help me.

We use CRM 2016. Today, the currency symbol in our CRM suddenly changed from € to £. I was able to change this back, but now, every monetary field keeps the symbol £. 

Even though we select EUR as our currency, we still e.g. get £ 100.000 when we type in the est. revenue for the opportunity. The currency for the account is also EUR, so that's not the problem.

Does anyone know how I can change the symbol back for the field Est. Revenue? 

Thank you in advance,

KR

Anneke