I'm hoping someone can help...

I took my 1 year old miniature schnauzer to the emergency vet
yesterday morning because all of a sudden he was limping and crying.
It got worse and he could barely even walk. Vet took xrays and stuff
and said nothing was wrong and we were to give him baby aspirin.
Today it was 10 times worse - we couldn't even get him to go outside
to do his business this morning. He couldn't walk at all. He laid on
the sofa shaking and in obvious pain. Took him back to emergency vet
and they did a Lyme test which came back positive. They also tested
his urine for protein - it came back with a trace amount and the
emergency vet wasn't concerned about that. So now he's on a 21 day
course of doxycycline, he already had his first dose, but he's in so
much pain!! He hasn't moved since we got home from the vet (at about
1PM today - it's now about 7:30). He's only gone "out" once today -
at the vet. He'll only eat a tiny bit of what we put right by his
face because he doesn't want to move. He's mostly sleeping, but
sometimes he's awake and looks around, and even wags his tail, but he
just can't move around. I'm trying to keep it together, but I just
see him and cry.
If he's this bad today, is he really going to respond to meds in 1 or
2 doses?Can I do anything to make him more comfortable? Vet said he
should feel better after only 2 doses of the medicine? Does that
sound right??? Is he going to be affected for the rest of his life?
He's seeing his regular vet tomorrow morning (of course they're not in
on the weekend), but I just want to try to do something to make him
more comfortable tonight!! I really don't know what to do and would
hugely appreciate any help.

Thanks
Joanne