Could my baby be teething?

My baby is 15 weeks and has been putting EVERYTHING in her mouth. She is getting really frustrated because its like she wants to bite on something. SHe has been drooling more and whining esp when her fingers are in her mouth. We have tried her pacifier, feeding her, but she has no interest in eating(shes eating, its just that that doesnt make her feel better) its like she wants to chomp on something. WHen i put my finger in her mouth she was very content biting hard on my finger, but i could not feel anything...maybe a slight bump here and there. Also she has been more restless while sleeping. Does this sound like shes teething? Ive tried the teething rings and she does ok with them but she gets mad when they dont stay in her mouth. ANy advise??