My cat freaked out on me??

so my cat has always been a pretty good cat well this morning she freaked out on me. i picked her up to put her out of our room and she let out a huge hissy meow and scratched the crap ot of me my chest and hands were full of deep cuts and once i got her off and closed the door she sat at the door and hissed for about five minutes. does anyone know why she would do this?? she is about 5 months old and has her shots but is not fixed yet.