Long heavy periods - please help?

No matter what birth control I'm on my periods are irregular and long... I'm currently on day 28 and it's extremely heavy (6 super tampons in a day) and it's driving me insane... Sometimes I'll get a week between periods other times it'll be months... 
It's happened on yaz, levlan ed, Yasmine, implanon NXT, without contraceptives and about 4 other pills... I'm over it,. 
Anyone know what it could be? Surely it's not healthy? Especially considering I'm iron deficient normally without the help of my period. How can I stop it? I also have cramps for the first time ever.... I'm 19, and only on implanon and norethisterone at the moment. 
Sorry for the long post, thank you.