I feel like a failure

Hello, I would really appreciate any advice or similar experiences… Does this get better?!

My son is 3-years-old. For the most part, he’s brilliant - very well behaved and well mannered. He is 3 and a half, to be exact, and I’d say quite clever for his age too.

But he has, for the past three days, made me cry every day. Suddenly I feel at my wits end. I’ve read a fair share of parenting books, and know he probably isn’t “purposely” being mean… but it certainly feels like he knows exactly what he’s doing.

Whenever I tell him no, or do something he doesn’t like, he’s lashed out saying some pretty harsh things. For example, “I don’t love you, I only like dad”…

What’s worse, I don’t even know what to say when he says things like that. He says similar things to my husband in the same scenarios, but he’s definitely worse with me.

He’s also just behaving differently to usual - despite having no routine changes. He’s more resistant to listen. More emotional, getting angry and lashing out more. I know these are completely normal things for a 3-year-old, and it’s not like he never behaved this way before, but it’s like all these behaviours have scaled up massively in both intensity and frequency. And he’s just damn mean!!

I’m at a loss. I feel like overnight I’ve lost my son? I know this sounds highly dramatic, but I just feel so out of my depth and overwhelmed about it.