Diva Cup issues?

Felicia
I'm wondering if I'm the only one have these problems with my Diva Cup. I've been using my diva cup for over a year now and at first it was great. I never leaked, there were no cramps and it even seemed like my period was shorter. After using my diva cup for several months I'm noticing that I have to wear pads with my cup because I'm leaking a lot more than before. I also had to cup the stem off my diva cup because it was just too long. Sometimes my diva cup keeps sinking down and just won't stay up. Once in a while I even have a hard time urinating with it in. Almost forgot one more thing, what menstrual cup do you use for a heavy flow? Why am I having all of these problems all of the sudden? Am I the only one with these issues going on? Do you think that there is a better menstrual cup out there?