Hello, my name is***** and I have over 20 years of experience as a veterinarian. I understand that you are concerned about your fellow eating almonds and now trembling and not himself.
Almonds are not toxic for dogs. However they are difficult to digest and are a high fat food so they can lead to nausea, vomiting and diarrhea, and if not thoroughly chewed up can cause a gastrointestinal blockage if several are eaten.
While one or two may be fine for some dogs others will vomit if given them, so in general I don't recommend that dogs be given nuts to snack on.
In your fellow's case he may have some stomach upset from eating an unusual food, thus leading to his behavior, or he may have eaten something else that you aren't aware of that is leading to stomach upset, or his behavior may be unrelated entirely. If he is reluctant to eat however it is worth treating him for stomach upset.
To try and settle his stomach you can try either:
1) Pepcid-ac (famotidine) at a dose of one 10mg tablet per 20 to 40 pounds of body weight every 12 hours.
2) Prilosec (omeprazole) at a dose of one half of a 20mg tablet per 20 to 40 pounds of body weight every 24 hours.
These will reduce stomach acid and should help settle his stomach. These can be used for several days as necessary as they are quite safe.
Then feed a homemade diet of 1/3 boiled, lean hamburger or boiled, white, skinless, chicken, all fats drained off the meat, and 2/3 boiled, plain, white rice. Add 2 tablespoons of canned pumpkin, (not pie filling, just pumpkin), to each meal for fiber if he has any mucousy diarrhea. Feed small meals several times a day.
Once he's feeling better then start mixing in his regular food, adding a little more regular and less bland at each meal. It should take a week or so to get him converted back to regular food.
If he starts vomiting, even after the acid reducing medication is given, refuses to eat or has explosive diarrhea it is best he see a veterinarian for an examination, injectable medications and oral medication like sucralfate to coat his gastrointestinal system.
As an aside macadamia nut ARE highly toxic to dogs.
Best of luck with your little fellow, please let me know if you have any further questions.