I have a 50 lb lab about 12 years...

Hello and welcome to Just Answer. This is Dr. Joey and it will be my pleasure to assist you with your questions today. I have over 20 years of experience in small animal medicine and surgery. I am sorry to hear that you are having trouble with your little one. I can understand how stressful it is for you. I will do my utmost to assist today and to see if we will be able to resolve this quickly for you. Please be patient with me as it takes time to review and write detailed recommendations.

Shortly you will receive an offer from Just Answer for a phone call, this is not directly from me and you do not have to accept it. If you prefer we can continue this whole conversation here. I will begin our discussion today with some questions to better understand your concerns.
To start with, in addition to this increased anxiety and restlessness, have there been any changes in eating, drinking, defecating or urinating most recently?
Are there any underlying medical conditions or medications that I should be aware of?

Wits this sort of acute onset restlessness dementia is less likely as that shows a more slow onset of unusual "forgetful" behavior. My top concern is something is painful for him, which might be his spine/back or something in his abdomen such as his gall bladder, liver, spleen or pancreas. Given that he is a larger breed dog with this I highly recommend have him seen today for an exam. We need to be absolutely sure there is not a bleeding tumor in his abdomen or back pain or gall bladder pain or pancreatitis. These can cause this sort of weird behavior where the dog isn't sure how to communicate something is wrong.

This is great that he will at least eat a treat and may suggest this is not a digestive tract problem. Please, let me know what questions you are still looking to have answered.

Yes, you can buy aspirin for pets. Or I like to recommend homeopathic arnica (trade name: T-relief) tablets that you give 1 every 12 hours. It is safe to use with all other pain relief products.

The T-relief (arnica) you buy at a regular pharmacy like CVS or Walgreens.