Possible teething?!

My daughter just passed 15 weeks and these past two weeks has been drooling uncontrollably biting her hands shoving her hand down her throat been crankier than usual.. I breast feed but lately have been giving her one bottle of formula here n there. I read it was a phase with the hands to not pay attention n she'll stop but she's just getting worse n sometimes while nibbling her fingers or hands she sounds like she's in pain.. Do you think she can be teething should I take her to the doctor?