Biting and lunging puppy

Hi all,

I’ve reached out on here for some advice before and taken this away but I’m still struggling with my 18 week Sprocker Spaniel biting and nipping.

She bites really hard sometimes, this morning I took her out of her crate for potty and she went for my leg/calve and nipped hard. I redirected to a toy and treated her. She does this everyday to the point I have to put her in her playpen till she settles. It makes training/ playing difficult, if she’s not napping she’s biting :/

She’s lost quite a few teeth over the last week and I’m ensuring she’s getting enough sleep/ mental exercise but this doesn’t seem to be helping?

I have puppy classes in a few weeks but I’m worried she’s going to be a nightmare!