I think my cat's pregnancy might have gone wrong. Might be an emergency?

I don't remember or even really know exactly when she got pregnant, but it was a while ago. But she's still really small and now she's acting how cats act when they're supposed to give birth. She's been really panicky the last few days, panting and running around and meowing a lot. And she tries to lead me into a box in a closet so I'm sure she's picked that spot out. Just today, minutes ago, she had some brown, blood-like thick discharge. I looked it up and apparently this is normal for cats about to go into labor.

But I still think it's too soon, and she's still so small. I'm worried about her, she might have lost the kittens but I can't be sure.

Is this how cats act when they lost them? I should probably call a vet, actually.