The last week my little one has been nervous, like when you put her do…

The last week my little one has been nervous, like when you put her down she starts shaking her arms and throwing tantrums. When she lies down, she chews on fists and fingers so hungrily ? She's tongue is always sticking out, with saliva flowing ? She can also lie down and whine, not in the sense of crying, but lying and making a whimpering sound, chewing on fists and whimpering). She used to be so sweet and babble, now she just screams ? Is this normal behavior? What should babies be able to do at 3 months old?