Mercedes was so confident her smear test would come back clear that she was chatting to a friend on the phone as she opened the letter.
But she was left shocked and confused when, at 24, she read that the cells in her cervix had started to change, caused by a virus called HPV (human papillomavirus).
Changes to the way smear tests work mean more women in the UK are about to be told they have HPV - but misconceptions around it can put a strain on sex, relationships and mental health.
Around 80% of people will contract one of more than 200 strains of HPV at some point in their lives. In most cases people don't even know they have it, and 90% of infections go away by themselves within two years.
In rare cases, like Mercedes', it can cause cell mutations that can ultimately develop into cervical cancer.
Mercedes had treatment to remove the affected cells and the virus had disappeared within six months. But the fact that she had contracted it made her feel anxious.
"I started to question: 'Where did I get this from? Is it something that I've done wrong?'" she says.
'It doesn't mean you're dirty'
Hearing HPV referred to as a sexually transmitted infection (STI) on TV made matters worse, leaving her feeling "dirty".
It seems she is not alone. A survey of more than 2,000 women carried out by Jo's Cervical Cancer Trust found, on average, 10% of women said they would feel the same if they were told they had it, and 57% said they might think their partner had cheated.
Under 25s were most likely to feel "dirty" (18%) compared to 12% of women aged between 25 and 34 and less than 5% of over 55s.
A vaccine for HPV has been offered to girls since 2008, and was made available to boys last year.
The virus lives in the skin around the genitals and can be passed on through sex (even if it's with a condom) and other intimate contact, so - technically - it is an STI.
But Kate Sanger, spokeswoman for the Trust, says that its prevalence means it is more comparable to a common cold than other STIs, so should not be viewed in the same way.
She is concerned about how the stigma could affect women now that changes to smear tests will lead to more diagnoses.
In the past, smear tests aimed to detect cell changes. But by the summer, all tests in England, Wales and Scotland are expected to screen for HPV first, to work out more accurately - and earlier on - who is at a higher risk of cervical cancer.
If both HPV and cell changes are detected, women will be asked to have further tests. But if HPV is found without any cell changes, they will be asked to come back a year later for a second smear to check the virus has gone.
"Being told you've got HPV doesn't mean you're dirty, it doesn't mean you've done anything wrong, it doesn't mean that you're any different to anyone else," she says.
"It's just like having a cold without any kind of symptoms."
Nicole Davidson, 26, from Suffolk, was told she had cervical cancer after her first smear test in 2018. She already had two children, and chose to have a hysterectomy as treatment.
Finding out that it was caused by HPV was an added stress. She had been with her partner for around five years, but began to question her sexual history and ended up taking anti-depressants.
"It made me feel like I'd caused it myself. I know it sounds really silly, but it makes you feel like if I'd never had sex, I'd never have got cervical cancer," she says.
Both men and women can contract HPV, but most men aren't aware because there is no test for them.
More than 40% of women said being told they had HPV would impact their dating and sex lives, with younger women being the most concerned.
Just 22% said they would date someone with HPV, and more than half would consider ending a relationship with a partner if they knew they had it.
Ms Sanger urges people not to panic if they are diagnosed - and stresses that while HPV is common, smear tests mean that cervical cancer is rare, with around 3,000 cases diagnosed in the UK every year.
'It's just natural'
The HPV vaccination programme for girls was relatively new when Nicole was at secondary school, and her mother did not get her vaccinated - a decision she says she will not repeat with her own children.
Now, almost two years on from her diagnosis and with much more knowledge about HPV, she says she is in a better place.
"It's just knowing that it's such a common thing and I didn't actually do anything to give myself cervical cancer," she says.
"It's not something that's dirty or disgusting, or anything like that, it's just natural."
'Part of life'
Unlike Nicole, Mercedes was in the early stages of a relationship when she was diagnosed.
"The emotional impact the whole thing had on me put a real strain on the relationship, because I just wasn't in a good headspace," she says.
"I didn't know very much about his sexual history and I never openly [or] actively blamed him, but I did start to question those things."
For her, feeling better was a question of learning about the prevalence of the virus and how easily it can be passed on.
Four years after opening the letter, and engaged to the man she was dating at the time, she wants other women to be more aware.
"It's part of life, it's just really unlucky that it affected the cells in my cervix," she says.
"It feels like a distant memory."