Hello all. I searched in the forums but didn't quickly see anything about this, so I thought I would throw out to the group to see if anyone has experience or insight to share... 

Background: Our loveable 5-year-old 80 pound Golden German had his left hind leg amputated five days ago (Osteosarcoma). He came home that evening and all has been going really well up until today. The day after surgery he went out on his own to pee, was eating well, seemed to tolerate meds well, etc. By day three his tail was wagging, he wanted to play, and it was all we could do to try to keep him from running around the house, yard, etc. Based on what we have read on this forum and other sites, we were (and mostly still are) quite impressed with his recovery. 

Current Concern: However, during the night last night, he leaped up out of a deep sleep yelping and crying out (presumably in pain?). This only lasted about 15 seconds (felt like a lifetime) but during that time he seemed inconsolable (almost thrashing around - that's a little dramatic but best description I can give). After about 15 seconds it all stopped, he sat there for a minute looking somewhat confused, then laid back down and went back to sleep. We have had two more episodes like this today - each with him jumping up out of what looks like a deep sleep yelping and crying. And about 15 seconds later, it all stops. But those 15 second episodes are hard to watch (and presumably not fun for the little guy either). 

Has anyone else had this experience with their pup post-surgery? I read somewhere about possible brief muscle spasms and wondered if that is possibly what is going on? Also, I kind of wondered if he was having pain dreams given that these three episodes have occurred when he is asleep (I don't even know if that is a thing). Or could he have overdone it yesterday when he was feeling good and is paying the price today (if so, that is on us as pet parents for not begin better about restricting his movement, not on him)?. Or could it be something else??? We have a call out to the vet, but haven't heard back. 

Additional Context: Rodeo is on the following meds:

Vetprofen - 75 MG (1 tablet every 12 hours) 
Trazodone - 100 MG (2 tablets every 12 hours - those seem to knock him for a loop so up until today we were just giving him 1 every 12 hours - that could have been a bad call on our part?) 
Gabapentin - 600 MG (2 tablets every 12 hours) 
Cephalexin 500 MG (2 tablets every 12 hours) 

He was also given some 3-day pain shot thingie right after the surgery (which presumably would have worn off a couple of days ago). 

Welcome any thoughts, advice, or experiences to share. Like all of you know, we just want our puppers to be happy and healthy and recover quickly and as painlessly as possible. 

Thanks,

Tommy