so heavy need help ;(

Ladies advice appreciated and urgently needed.... After 2 kids and pill periods of 5 years i changed to the non hormone coil 6 months ago. since then on day 2 and 3 of my period i am flooding mooncup (lge), ladycup(lge) and meluna (medium) every 2 hours at 15mls at a time and with super plus tampax its every hour that i flood . I feel so down about it and have booked in for mirena coil but i dont react well to hormones and so really dont want it to happen but i cant be like this at work. i also have had no other unmanageable symptoms and am really well so would like to keep the coil i have. Ive used menstrual cups for 3 years so know about seals etc. I am taking ponstan now at start of period but its not helping to ease down the flooding. To be honest this was me from 11 - 16 years old till i started the pill so its obviously my periods naturally.

Can anyone recommend a cup i can try that holds large amounts and is firm. Out of all my cups i prefer the meluna for its firmness. I have a week before hospital appointment so advice appreciated x