What's wrong with my cat?

So, for the past few days my cat has been acting extremely strange. Yesterday, I was laying in bed and my cat usually comes and cuddles with me, so that's what she did. She layed beside my thigh while I watched netflix.

It was all causal and normal, until I tried to get out of bed, and she growled at me, which scared me. I kept trying to move, and she growled and growled.
She then started to hiss, and attack me with her paw. She even tried biting my arm, and succeeded.

But, she only did this when I tried getting out of the bed. Otherwise, she was fine and went back to trying to sleep.
She has done this before, but, what's really making me ponder now is why she isn't leaving my bed.

Today, she's entered my room in the morning, and hasn't left since, and it's already the afternoon.

She's still eating and drinking, and being normal... But just besides the violent episodes when I try to get up, and not leaving my bed at all today. Also, with any little noises she hears, she growls too.

She's healthy, and only about three or four years of age. I wouldn't say I'm worried, but, of course I'm just looking to see if anyone knows what's was going on with her.

What else is a little odd is that she only does this with me. She doesn't get violent with any other family member except for me. It's almost like she's protecting me, or something along those lines...