Toy poodle squeals when touched..?

[Danka2106]

I have a neutered male toy poodle who is only 2 years old. 2 weeks ago on Tuesday night he began to vomit, initially we had thought the vomiting was due to overeating as he had eaten more than usual and the vomit was undigested wet food. After that up until Saturday he began to slowly lose mobility and became more and more lethargic. On Saturday we took him to the vet because he was unable to jump (he can usually jump very high and is excellent at agility), he struggled to walk and squealed when picked up. The same thing had happened a year ago around the same time of year , but he was given a metacam shot and was fine the next day and from then onwards. When we went this time, he had a temperature of 40.5 °c and the vet suggested he could have a slipped disc or an intestinal problem.The vet had did if it was a slipped disc the vomiting could have been caused by a sudden pressure, however she also said a slipped disc isn't something that would go away and come back a year later.  Both this time and the year before the vet had noticed a tenderness in his hindquarters.. He was given a metacam shot as well as metacam medecine. On Sunday evening he began to have blood in his faeces so we were told to stop giving him the metacam. By Wednesday, he wasn't drinking or eating and generally was not getting better so we took him to the vet again. The vet gave him an antibiotic and pain killer in the form of shots. His temperature was 40.2°c . She then told us to come back the next day and if he was not better they would have to take him in overnight to do some blood test, x-rays etc. However the next day we took him in, he was generally more lively and his temperature had dropped to around 39.2°c (although this still may seem high, he is a very nervous dog and since he was a puppy his temperature has never been below 39°c at the vets) so the vet gave us antibiotics to take twice daily and pain killers for when he seems to be in pain. Currently he is still on the antibiotics and he seems very happy and lively and keeps his tail up high and wagging. However today I had to give him a pain killer as he has become very sensitive and whenever he is touched or he attempts a jump he squeals loudly. He is also very skittish and has recently been very startled by even the slightest movement. Any help would be appreciated as we are very worried about our little fur baby.