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What to do if…
you develop a fever that rises quickly and you feel unusually weak

Produced and maintained by PanicStation.org Published: Last reviewed: Editorial policy UK guide

Short answer

If your fever is climbing quickly and you feel unusually weak, get urgent medical help now. Call 111, or use 111 online where available if it is suitable for your situation, and call 999 or go to A&E immediately if you have emergency warning signs or think meningitis or sepsis could be possible.

Do not do these things

  • Do not “sleep it off” alone if you feel unusually weak, faint, confused, breathless, or you are getting worse.
  • Do not drive yourself to A&E or urgent care if you feel weak, dizzy, faint, or light-headed.
  • Do not take extra doses or combine cold and flu remedies without checking, especially because several products can contain paracetamol.
  • Do not try to force your temperature down quickly with ice-cold cooling or by making yourself shiver.
  • Do not take leftover antibiotics or someone else’s prescription medicine.
  • Do not take ibuprofen if it may not be safe for you, for example if you are pregnant or trying to get pregnant, have had a stomach ulcer, have asthma or allergies, have chickenpox, have heart, liver, or kidney problems, have blood clotting problems, have had a stroke, or have been told to avoid ibuprofen, aspirin, or other NSAIDs.

What to do now

  1. Check for emergency warning signs. Call 999 or go to A&E now if any are present:

    • acting confused, slurred speech, or not making sense
    • difficulty breathing, breathlessness, or breathing very fast
    • blue, grey, pale, or blotchy skin, lips, or tongue; on brown or black skin this may be easier to see on the palms or soles
    • being very sleepy or difficult to wake
    • collapse, or a fit or seizure
    • a rash that does not fade when pressed with the side of a clear glass

    If you have darker skin, a rash can be harder to see. Check paler areas such as the palms, soles, roof of the mouth, whites of the eyes, or inside the eyelids.

  2. If you do not have the emergency signs above, still treat this as urgent. Call 111 now, or use 111 online where available if it is suitable for your situation, if any apply:

    • you feel very unwell or like something is seriously wrong
    • you have not had a pee all day, or you are peeing much less than usual
    • you are shivering a lot, or feel very hot or very cold to the touch
    • you have swelling or pain around a cut or wound
    • the fever is getting worse despite home care

  3. If you are alone, get another person involved. Ask someone nearby to stay with you or check in frequently until you have been assessed or are clearly improving. If nobody can come, tell 111 that you are alone and unusually weak.

  4. Write down a few key observations for triage.

    • Your temperature, if you can measure it, when it started, and whether it is rising quickly
    • New or worsening symptoms, such as confusion, fast breathing, chest pain, stiff neck, dislike of bright lights, new rash, vomiting, or diarrhoea
    • When you last peed, and whether it is much less than usual
    • Recent triggers or risks, such as a recent infection, surgery, procedure, wound, catheter, travel, diabetes, immune suppression, or immune-suppressing medicines

  5. Use simple, safe comfort steps while arranging care.

    • Sip fluids regularly; take small sips often if you feel sick.
    • Rest somewhere safe, where another person can reach you.
    • If you feel uncomfortable, follow the packet or leaflet for paracetamol.
    • If you are considering ibuprofen, only use it if it is normally safe for you. If you are unsure, ask 111 or a pharmacist.

  6. Be ready to go in quickly if advised, or if you worsen.

    • Have your medicines, medication list, allergies, and key health conditions ready.
    • If you are told to attend A&E, do not drive yourself. Ask someone to take you or call 999.

What can wait

  • You do not need to work out the exact cause of the fever right now.
  • You do not need to push through weakness, finish tasks, or prove it is serious before seeking help.
  • You do not need to keep re-checking your temperature repeatedly; focus on whether you are worsening and on the warning signs above.
  • You do not need to make longer-term decisions until you are safe and assessed.

Important reassurance

A fast-rising fever with unusual weakness can feel frightening, and it is reasonable to treat it as urgent. Getting assessed early is a protective step, especially when you feel significantly weaker than normal.

Scope note

These are first steps only, aimed at keeping you safe and getting you to the right level of care quickly. Later decisions may need help from a clinician or another suitable specialist.

Important note

This guide is general information only. It is not medical, legal, financial, therapeutic, or other professional advice.

Additional Resources

Closely connected guides that may be useful during the same situation or its immediate aftermath.

About this guide

This guide was produced and is maintained by PanicStation.org using its published editorial process. Official and specialist sources are checked where relevant, and AI-assisted tools may be used for drafting, organisation, and consistency checks. The site operator remains responsible for publication, revision, and removal decisions.

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