We all have those moments where we walk into a room and forget what we're looking for.
Or you might go upstairs to fetch something, only to come back down empty-handed after getting distracted.
But when Sam Wells couldn't remember why she went into her local supermarket, it was the start of a life-altering health battle for which there is no cure.
The 48-year-old mum-of-two was shopping back in 2019 when she experienced complete brain fog.
She couldn't for the life of her remember what she had intended to buy, and eventually walked out empty-handed.
The NHS specialist nursery nurse later developed an odd flicker in her eye and questioned whether she had suffered a mini-stroke.
Sam, from Penkridge in Staffordshire, went to Royal Stoke University Hospital where she underwent an MRI - only to be told she had a mass on her brain.
She was immediately sent into surgery in a bid to remove the growth before they stapled her head back together.
Then came the life-shattering diagnosis that she had a grade 3 anaplastic astrocytoma - a rare malignant brain tumour.
Since then, Sam has undergone serious treatment, including surgery, 33 sessions of radiotherapy, and a year of chemotherapy.
"I had no idea what having a brain tumour meant," Sam said.
"From that point, everything was rushed. I wasn't allowed to drive and had to call my husband and tell him the news.
"Next thing, I was having surgery where I had about 70 per cent of the mass removed.
"I came out with 48 staples in my head after which I was referred to an oncologist who confirmed the mass was cancer."
Sam now has to have regular scans to monitor the growth of the remainder of the tumour and is on life-long anti-seizure medication.
Despite what she has been through, she is determined to make the most of the now.
Sam added: "Everyone copes differently when faced with something so huge. For me and my family, we know there may not be a long future, so we feel encouraged to live in the present.
"It's not about creating bucket lists but about living in each moment we get to spend together."
And although she is having ongoing treatment, Sam has decided to run a month-long marathon challenge this May to give back to the science that has helped her, raising vital funds for Brain Tumour Research.
The Jog 26.2 Miles in May challenge, which is now in its third year, was set up to raise money to help find a cure for brain tumours.
Sam admits she is no runner, adding: "I've got a decent walking pace... so far it's been good to get out and I've completed seven miles.
"I have had amazing support from my teenage daughter, Megan, who is doing it with me alongside Woody, our Labrador-spaniel cross."
The symptoms of a brain tumour vary depending on the exact part of the brain affected. Common symptoms include: headaches, seizures (fits), persistently feeling sick (nausea), being sick (vomiting) and drowsiness, mental or behavioural changes, such as memory problems or changes in personality, progressive weakness or paralysis on one side of the body, and vision or speech problems.
Mel Tiley, community development manager at Brain Tumour Research said: "We’re extremely grateful to Sam for sharing her story and signing up to support the charity with an epic month-long challenge.
"Her willingness to share her story to raise awareness will help us in our vision to find a cure for all types of brain tumours.”
Brain Tumour Research funds sustainable research at dedicated centres in the UK.
It also campaigns for the Government and the larger cancer charities to invest more in research into brain tumours - which kill more children and adults under the age of 40 than any other cancer.
You can donate to Sam's challenge here: www.facebook.com/donate/1253219945567166/
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