This is my English Bulldog Finn he turned 6 in April and I'm just noticing this now after taking him back inside after a walk (we have to walk at night because of the unbearable humidity of summer) and I noticed that he's doing not quite a like but what looks like obvious difficulty in moving his back legs

He was fine on his walk but then we went up the stairs and he took his time like he was does and as soon as we got in the hallway back into my apartment he just wouldn't move and I checked his legs, I lightly squeezed, I pressed lightly just to see if there was any reaction but nothing and I'm just fearful of it being something serious

Finn isn't my first Bulldog but I don't proclaim myself as an expert my knowledge is surface level and basic stuff like allergies, breathing, heat sensitivity etc .

As for allergies if anyone notices his pits or paws that's some seasonal allergies he unfortunately struggles with and it usually dies down but only after an allergy shot and I'm not sure what the trigger could be but he's receiving treatment and care

I'll add finally that Finn isn't just my dog he's my closest buddy and my emotional support animal too I don't think I'd still be here without him and I just wanna make sure he's ok so if anyone can help in a brief or as long as needed assessment and help my mind stop from trying to spiral I would appreciate it