My dog recently underwent heartworm treatment with Immiticide. He received 1 shot on June 15th, then on July 15th he received another shot, followed by a 2nd on on July 16th. The first month, he also took an antibiotic each day and 10 mg prednisone every 48 hours. During the second month, he continue the prednisone every 48 hours. He has done fine and has been restricted from major activity, other than going out to the bathroom. He is eating/drinking okay and has had normal bowel movements, etc. 2 days ago, he started trembling non-stop and would whine as if he was hurt when he moved his legs...he would often stand very still and not move and was hard to get to lay down or sit. He would also begin panting while shaking. He appeared okay yesterday morning, but started it again by evening. It seems to come and go. Any help on what might be going on is appreciated.