You were both so blessed to have each other and to have such a wonderful reaction to chemo. =)
However, from what I've seen with many, many others, your baby was the exception, rather than the rule. Possibly because of all the additional supplements, possibly just one of the "luckier" ones (and yes, I know that is a very relative use of the word) who can say for sure. I've just seen too many animals - and people - go through awful, painful, lingering deaths on chemo and radiation.
Just a few months ago, we buried my aunt who required morphine (the only painkiller that had any success at dulling her pain towards the end) her last 4 months of "living". Morphine loses it's effects after a while and needs to have the dosage increased. They finally had to stop increasing because the dose of pain medication alone was bordering on lethal. It truly was a blessing for her to finally pass as she was in agony and she always complained of feeling so much worse after therapy/treatments.
I've seen many animals go through the same pain, but they couldn't speak to say how badly they hurt. However, their eyes would give it away. They'd gamely try to follow old routines, especially when they're owner was showing them attention, but otherwise would spend hours just lying there, trying to find comfortable positions. I believe it is those that I and Blueduck are speaking of.
I'm so very glad to hear that you and your baby fared much better. You can have fond memories. Many others spend almost every minute second guessing "is this right?" because the quality of life *isn't* good, it's miserable. But, animals will keep fighting as long as they believe we're fighting, sometimes very much prolonging their pain out of their love for us.