My Two Cats got lasy

Hello everyone...
I have a problem with my two cats, they are Siames Cats and just 5 months old. From one day to the other they got really lasy, sleeping the whole day and their legs hurt, first the front legs and now the back legs. It is very weired, im hoping that somebody can help me out.
The vets are very very expensive in my area and i already went there many times for other things

Thank you

There must be a good reason why there has been no response since yesterday morning?
Is this a dead thread? Just wondering...

I'm not familiar with this problem, but are both cats having the same problem? :confused: I'm sorry to have to say, but I think another vet visit is really important.