I wouldn't be concerned about the lack of feces since 4:30 this morning. When pets are having diarrhea, they will clear their bowels quickly from the diarrhea and, thus, produce feces less often. It's common for 3-5 days to be required for pets to produce regular bowel movements following a GI upset.
The shaking and panting may be due to nausea now that he's eaten dinner. It's not uncommon for nausea to accompany diarrhea. I would recommend that you administer a dose of regular pepcid (famotidine) every 12-24 hours. You will want to give 0.5mg/pound of body weight (a 10# ***** would receive 5mg, a 5# ***** would receive 2.5mg, etc). For this, you can visit any human pharmacy and buy the OTC brand name Pepcid, or you can use the cheaper, off-brand “famotidine” that’s available. Either will be useful. For pets avoiding taking medication readily, you will likely need to using a pilling technique like this one: https://www.youtube.com/watch?v=-P6NfbxeLX0
If you haven't already placed him on a bland diet like boiled rice and chicken, that may also help calm the symptoms of panting, shaking and the diarrhea. If the symptom persists, I would recommend a vet visit. They will likely want to run bloodwork and a fecal examination to see if there is a cause for the diarrhea, which might also explain the additional symptoms you've witnessed.
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