Menstrual cup leak?

Ürün

Hi! That's my second period since I started using a menstrual cup and I was sooo happy with my first experience that I didn't thing twice. But this time, with the same cup, I had leaks, twice. And as you may guess, it was not just a drop!

It was on my second day (in a concert lying on the grass) and next morning (lying in bed), with very heavy flow. I assume because the cup was full both times and i squeezed my muscles stretching.

Did you experience any leaks? How do you avoid them? Do you think I should use a larger cup for heavy flow days?