my girl is acting strange?!?! what's going on?

my 18 mo old daughter is starting to worry me. She doesn't want to eat, she doesn't want to take baths and she used to love them, she's not wanting to use words, and she's fussy all the time, has started biting people, insists on being rocked to sleep, has become momma clingy(always wanted daddy for everything before), doesn't want to wear clothes. all within the last 2 weeks everything is changing and I don't know what to do. and what this is? she has always been low maintenance and such a sweet heart, and now she is freaking me out and I'm exhausted, I also have a 6 week old baby boy now and between the 2 I'm going crazy, what can I do?