Toddler has become aggressive

My baby is 30 months old, started picking his words at 20months.

Smile and waves back at me and we even have a way of greeting each other like a sign.

All of a sudden he withdrew after I came back from 5weeks holiday and I thought it's was because had been away far too long, but I noticed he wasn't waving as usual and I realise the only words he could pronounce now are Daddy and mummy.

He's so aggressive and will not respond to his name.

I am worried as a father.

Could there be something wrong?