Low wbc and neutrophillis count when bloods from 2 months ago were normal- possible reasons for this?

Repeat test: This is not an uncommon finding. Sometimes it is reaction to a viral infection. There is something called benign ethnic neutropenia. Some medications can cause it eg clozapine, cotrimoxazole, valproate. If you are otherwise well then the only thing needed is a repeat blood test in a few weeks time to ensure it has corrected. If not your Dr may discuss further with a haematologist.

How low?: Mild lowering can be common in viral infections and often a repeat test several weeks later will be normal. Borderline outside the normal range may be normal for you. Medications can cause it. If unwell/fevers and low then must seek urgent medical attention to exclude infection or serious blood disorder. Recommend seek specific advice from your GP or the doctor who ordered it to sort it.

Low WBC : Commonest cause is the viral infections . Other causes may include any disease that cause bone marrow suppression. Need to talk to your doctor as the cause has to. E put in context with your situation. Not a good idea to google causes and apply to your situation .