Why is my baby Cal Kingsnake behaving like this

[kingsnakes]

Hi all,
I have just bought a baby Cal Kingsnake, when I first brought her home she was very agressive not a happy snake at all. I got some good advice from others and was told it was probably the moving of new home for the snake that was making her so agressive and that she would settle down in time, and this is what she did, I was able to handle her for 15/20 mins a day without any problems. The problem I have now which is puzzling me is, I fed her for the first time 2 days ago, I gave her two pinkies which she had no problem at all with. Today I went into her tank to change her water and handle her for 20 mins and dear or dear she is extremely agressive, she is striking at me, striking at the glass when I'm away from the tank, vibrating her tail if I even move, she wasn't this bad when I first brought her home.Have I done something wrong while feeding her? Would really appreciate some advice on why my snake is acting like this.
Cheers...