Friend, I am so sorry that you are having this problem with your puppy. The symptoms that you are describing are consistent with neurological signs which could be caused by toxicity, infections, etc. I am not 100% sure if this is related to the chemlight. You see, most glowstick are non-toxic when ingested. However, they can be irritating to the gastrointestinal tract causing symptoms like vomiting, diarrhea, abdominal discomfort, etc. So, I suspect either he got into something toxic or there is something else going on. As far as the sandwich and mac cheese, I would also expect gastrointestinal symptoms.
Unfortunately, in this case, we are very limited as to what you can do at home, I am sorry. I would strongly recommend having him checked tonight by ER veterinarian. There is really nothing I can recommend for you to try at home that is going to have a significant therapeutic benefit, I am sorry. I realize that this answer may not be entirely to your liking, and I regret being the bearer of information that you really don’t want to hear. But it would be unfair to you and unprofessional of me were I to provide you with anything less than truthful and honest information. I hope you understand.
My goal is to provide you with excellent service - I hope I've provided the information you were seeking, if you feel you have received anything less, please reply back as I am happy to address follow-up questions. Kindly rate me when you are done.