The meaning of snakes and Crocodile's in a dream?

In my dream a crocodile attacks me, my sister in attempt to rescue me turns the crocodile towards herself. The crocodile is chewing on my sisters leg and im trying to get it off. Then i see a snake coming towards me going through a doorway. The whole time my mom is watching and isn't helping.I'm very afraid of snakes can you please help me? I don't know what this means