My English Bulldog Will Be 10 This October Today I

My English Bulldog will be 10 this October today I came home from work and he is unable to bare any weight on his back legs. When I can get him on his feet and he attempts to walk he looks like he is having issues making all 4 legs move at once. I gave him a baby Aspirin thinking he may just be having some arthritis pain but it does not appear to be effective. Any ideas? I am very concerned.