How do you know if a period is heavy?

[LlamaNoDrama]

Which sounds like a very stupid question but I just don't know.

I use a cup and have done for years. The last 18 mths or so on the second day of my period, which is the heaviest, I probably empty it every 2/3 hrs but I can't figure out if this is a lot or normal? I have a luna shorty so it probably holds a bit less than some other menstrual cups, around 18/22 ml or 10/14ml to the capacity holes which is when I assume it starts leaking. I usually wear a cup and period pants whilst out during the first 2-3 days of my period due to this.

I was just reading you lose 5-80ml per period (who are these lucky buggers only losing 5ml per period?!) so if I'm emptying mine several times over a day then that's a lot?

With flooding there is no way I could use a cup. It would fill in 10 mins. But flooding is different to the standard 'heavy'

I kept a record of much blood I lost by writing down each time I emptied a full cup over several periods. Mine was 10x the upper end of "normal" range and when I reported to the GP it was investigated and found I had very large fibroids. Also unsurprisingly anaemic.

Editing to add that I emptied my cup every 30 minutes at times and I could not leave the house.