Decreased milk feed and drooling

I have come across articles on milk strike and possible teething at 4 months old but I’m not too sure if my baby is experiencing it. Noticed extra drooling since 3m until now, recently likes to suck her hand/ put things into her mouth and suck. She no longer enjoys drinking milk even though we give her her preferred breastmilk. Milk demand has dropped as well. Not too sure if it’s related to her recent vaccine.