It was a momentous moment and I was alone, overwhelmed and embarrassed.
So I cried.
I sat in that toilet cubicle for what felt like forever until a friend came to find me and, after telling her what had happened, she came with me to ask the office lady for a pad.
Once I managed to convey my message - even just saying the word "pad" in public felt worthy of embarrassment - the office lady rustled around in the office and returned with the required sanitary product and told me I could use the teacher's toilet to change.
It was an awkward encounter for me because I didn't know how to talk about menstruation openly but when I think back to that time, I have always been grateful that at least my school had supplies on hand to help young people through that process.
Up until now, not all schools have been able to provide that, or if they have, it's usually been out of the school budget.
But last week the Prime Minister and Associate Minister for Education Jan Tinetti announced the Government would roll out free period products in all schools following a successful pilot programme in the Waikato.
Not only will this ensure the next generation of young people are never caught out lacking supplies, it will also hopefully help destigmatise a natural bodily function experienced by half the population.
If more people are able to talk about menstruation openly our young people may be able to avoid that feeling of desperation and shame some have felt in the past.
It won't be such a big deal to ask the office for a sanitary product because children will see adults treating the subject with maturity and openness and will follow suit.
No student deserves to be disadvantaged by something they cannot control.
Helping our young people through a time where they feel most vulnerable is a win for everyone and another step towards making our schools safe, inclusive and supportive spaces for all.