Hissing and edgey

I made another thread in the Behavior section but someone said i should try and post it here... I might get some more advice soooo..

My cat gave birth about a month and and she has been fine until now. For the past couple days she has been acting differently. Her baby is kept in the basement in the back corner, but now when we go downstairs she sits near the stairs and hisses at us when we go down.. But right after she hisses she meows like she always does.

Also, she runs up the stairs now and runs past us on the main floor like we are scaring her, but we are not doing anything differently ..She does it like something is scaring her.
Earlier today she came up the stairs and from where the door is you can see straight into the kitchen, so she walked towards the kitchen and hissed at my grandma, and my grandma wasnt even aying attention to her she was by the stove cooking something.

She has been acting very on edge lately, does aanyone know what it might be from?

I don't have any experience with new mama kitties but I agree with what was said in the other thread. A sudden change in behavior is frequently a sign of illness. A vet visit might be in order.

I didnt see the other thread (will look there next). But my first reaction is she has a suffering somewhere.

The other possibility she is thouchy now when her babies are moving around now. Right?
But she should be touchy around them, not in the kitchen where she nor the kittens has anything to do.

And it just may be she's in heat again.