My wife and I took in a stray beagle three months ago. She was a sweet dog who enjoyed playing with our lab and pitbull. She had heartworms which we just finished treating for and also was beginning her heat cycle. 3 weeks ago the cycle started to end (evident by her no longer having an interest in the two males in the house). However, her temperament has completely change. The sweet beagle we found has turned into a lethargic, [censored], and biting dog. If this something that will pass, or do I have larger problems on my hands?