Dog Arthritis Treatment

My dog (chiguagua) was perfectly fine on saturday night when i got home(1130pm) and on sunday morning he didnt get up with me like usual. after a while i noticed he couldnt walk…and thorughtout the day he had symtoms of a siezure. (stiff back legs, one front paw lifted, dis-oriented, staring into space and would scream if you touched him at times) toke him to the vet and said he had signs of arthrits. but im not doubting the vet opinion but how could my dog go from playful and happy to miserable and doesnt even wanna get outta bed overnight? (7 hours) its been four days and no change…im confused.

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