T.W.
She's probably teething. Does she have any teeth? My daughter got her first tooth at 3 1/2 mo, her 20th & last tooth at 17mo (yes, she was a very early teether). She didn't sleep through the night 'til all her teeth were in! Coincidence, maybe, but I think teething really bothered her. Neither Tylenol or Orajel really worked...we gave them to her (or homeopathic teething drops) if absolutely necessary, but it didn't cause her to sleep through the night.