weight loss, odd head movement every 20-30 seconds, strange gait, smacking mouth

Our cat has suddenly lost weight, 300g in around a week. Has an odd "kick" or slight movement of his head every 2-30 seconds. Seems listless and floppy. Certainly not himself. Off his food. Coat seemed matted/hard and congealed in places a few days ago. Please help

He was 5.15 kg about a week ago. Now 4.85kg. Lives in town and goes out of his own free volition via cat flap.

About 7 years old. Taken in by partner after feeding on street for over a month, followed her home; this was about 4-5 years ago.

Hello. So your cat is listless, floppy and making sudden movements of the head.  This sounds very concerning to me and as though it may not wait.  Please do call your emergency vet for triage.

I am wondering about things like nausea (but with weakness) or part of a neurological episode, such as a fit.   Your emergency vet will be able to help to rule these in or out and will be able to see the patient if necessary.

Thank you very much for your time. Contacted Emergency 24 Vet. Very helpful. All symptoms reported. 09:30 hrs appointment, 12 hours from now. Cat sleeping currently.

The last post I wrote wasn't published. Now been to see a proper vet. Questions of why the last one did not take his temperature which was 41C. [!] Medication from the last was said to be not needed and useless in this case of Cat HIV; which was tested there and then and antibiotics given to see if he responds, follow up appointment tomorrow. Bloods taken for test, just about the same money.   Can you advise where to report a suspected fraudulent vet working here possibly with fake certification?   Thank you