The signs of ketosis are real but easy to misread. Tick what applies and you will get a plain read of how likely it is, and what actually confirms it. For the certain answer, see measuring ketosis.
This is a rough guide based on the common symptoms of ketosis, not a measurement. Symptoms overlap with plain dieting, dehydration and ordinary tiredness, so they can mislead in both directions. The only reliable way to know is a blood ketone meter (breath and urine are cheaper but rougher). None of this is medical advice; if you feel genuinely unwell, are on medication for diabetes, or have a health condition, speak to a doctor rather than relying on symptoms.