• I feel really rough.
• I'm shattered.
• I'm on my last legs.
• You look poorly.
• You look like death warmed up.
• You're looking peaky.

• I feel great! / I'm on top of the world / I feel like a million dollars! - I couldn't feel any better!
• He's glowing with health. - He looks very well.
• I'm a picture of health. - There's nothing at all wrong with me.
  
  

• She's sprained / twisted her ankle / wrist. - She's damaged her ankle or wrist in a fall.
• She's broken her arm. She'll be in plaster for weeks. - Her broken limb is in a hard plaster cast.
• My back aches / I've got backache - I have a sore back.
• I've got toothache. / a headache. / a stomachache. - These are phrases using -ache to describe what hurts.
• I feel sick. - I'm feeling nauseous.
• I think I've got food poisoning. - I've eaten something bad and I feel unwell.
• I've got a really bad cold. - I've got a temperature, a sore throat and a runny nose. [A typical English winter infection!]

• Make an appointment at the doctor's / the GP. - Go and see the general practitioner.
• I've been referred to a consultant at the hospital. - My doctor has arranged for me to see an expert at a hospital to help me recover.
• I need a check-up at the hospital. / I need an X-Ray. / an examination. / a scan. - These are treatments you might need at a hospital.
• I need to see the specialist- someone who knows about one health issue in particular.

• Consult your doctor if symptoms persist. - If you still feel ill after taking the medicine, see your doctor.
• Do not take more than the stated dose. - Don't take more [pills or medicine] than you're told to.
• Always read the label. - Make sure you take the advice given on the medicine container.
• Keep out of the reach of children. - Do not let children play with the medicine or its container.

You will also hear:

• 'She's a pain in the neck!' and 'she's a pain in the arse!' (this is very impolite!) - This doesn't mean she's ill - it means she's very annoying!