Do I need a doctor?

[Ehhn]

I don't know whether I'm just run down or whether I have something more serious.

Photosensitive headache
Achey joints
Nausea
Fatigued but unable to sleep properly

But I'm self employed and I can't miss any work. I also work part time at a prestigious university (v lucky to even have the work) and I have 55 papers to mark (ok, done about 35 of them) and a lecture to write.

How long have you had the symptoms and have you tried paracetamol, ibuprofen etc?

I took tramadol for the horrendous neck and back pain but it didn't touch it. I had 500 mg of paracetamol which also didn't work. Had symptoms since Sunday. One night of feverishness, but not since.

I'd try and make an appointment - they can't force you to stop working (even if it would be advisable!).

I'd get yourself checked out, if tramadol is not touching the neck pain, combined with photosensitivity, it's best to go and get seen as soon as possible.
These could possibly be symptoms of viral meningitis, and it's really, really worth getting checked out.