It would be worthwhile to have update bloodwork performed as well as a urinalysis. It's not uncommon for us to see that conditions like a urinary tract infection, diabetes, kidney disease, liver disease, prostate issues, Cushing's disease, etc. causing an increase in the need to urinate and, as well, an increase in fluid consumption. We can also see shaking with development of illness which can indicate anything from discomfort to anxiety. Being whole without the option to breed can cause anxiety in males, but I don't think that is what he's experiencing (at least not exclusively). If he's not going to be used for breeding, you may wish to have him altered so he's not exhibiting signs of aggression, sexual frustration, etc. The humping behavior may be sexually-connected or could also simply be due to dominance.
In the interim, I can give you some steps to take at home to help your companion’s stomach feel better. However, if you do not see a marked improvement from your pet or you see worsening of symptoms, they absolutely must be examined by a veterinarian.
It often helps to give something to calm the stomach and a bland diet with higher fiber. This can help to reduce the instance of nausea/vomiting, avoid or address changes in the stool, help to move ingested items through the GI tract, etc.
The first step is to 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
2 hours following a dose of famotidine, the time needed for the medication to begin working, you can offer a bland diet. To make this, you’ll combine white or brown rice, boneless, skinless chicken breast and sufficient water for cooking in a stock pot. Boil on medium until it turns to mush and the breast is easily flaked. To avoid more nausea, start with small amounts to begin with and offer the amount every 2-4 hours. A few teaspoons to start is typically sufficient and you can work your way up every 2-4 hours in incremental increases until you’re sure no vomiting will be seen. If your companion requires a more palatable food, try adding in pureed baby food in chicken, turkey and similar flavors. Avoid those that contain onion or garlic in the ingredient panel. Work up to feeding exclusively until at least 3 days following the resolution of the GI upset. After this, work on slowly switching back to the regular food that your companion typically eats.
I will be standing by if you have other questions. Let me know if I can help further. Also, before signing off today, please take the time to use the star rating system at the top of the page to leave a rating for me. Until this is done, the website will not compensate me for helping you. You will still be able to chat with me even after issuing a rating.
I will also check in with you over the next few days for updates on your companion to be sure you don’t need any additional assistance. Letting me know how your companion is doing would be greatly appreciated. If you would like to request me in the future for pet-related questions, you can do so by accessing this page: http://www.justanswer.com/pet/expert-pitrottmommy/?rpt=3800