Birmingham, UK - Bella Kilmartins is physically un able to enjoy the funniest moments of her life – because she literally misses them.

Bella's problems started when she was still in school. Every day, it got harder and harder to keep her eyes open during class.

Something wasn't right...

The UK native didn't waste time. Like any good student, she did her own research and then took her findings to the doctor, who confirmed what she suspected: Bella was showing symptoms of the sleep disorder, narcolepsy.

As the Daily Star reported, she was finally diagnosed in 2015, just before graduation - but that was just the beginning of her journey.

When she then saw a specialist, he discovered that she also suffered from cataplexy: brief episodes of muscle failure triggered by strong emotions - in Bella's case, laughter.

She described a typical attack: "My knees go weak, my head droops. I’m conscious and aware and able to hear everything that is going on, but I just can’t move my body at all. There have been many times that I’ve knocked a hot cup of tea over myself but couldn’t move my arms to stop the tea going all over me."

This is all no laughing matter: "I can’t control where it happens, so it can be quite scary. When the cataplexy initially started, I’d feel light-headed when I laughed. Then it progressed so that my eyes would flicker and my eyelids would go all droopy."

It has since gotten worse, so that her knees become weak as soon as she starts laughing. While she is conscious at such moments, she is no longer in control of her body.

Cataplexy can prove really dangerous, particularly during activities that wouldn't be considered safe should she ever fall asleep.

For example, Bella shares, "Something funny happened once in a pool – I don’t even know what – and I ended up starting to laugh. All of my muscles went weak and my head started drooping under the water."

"Luckily my friend knew about my condition, so she swam over and had to keep my head above water so I didn't drown."

Today, her main aim is to make other people aware of her condition and to give encouragement to people with a similar diagnosis!

"Reading about other people's experiences has really helped me, so that's why I wanted to share my story," she told the Daily Star.