Whew, I had a hard time figuring out how to post; hope this works!

I've been using a MeLuna Mini (I guess comparable to the MeLuna Shorty M now? I THINK at the time it only came in their softest material) since January 2014, so I'm not a newbie by any means. I'm used to popping it in, changing every 12 hours, and forgetting about it. It's been wonderful.

Well, the past few cycles, my cup has started leaking 2-3 hours after I put it in. Not gushing, but more "spotting" I guess, that increases as time goes on. When it starts leaking, I take it out to change it and it's maybe only about 1/3 full. When I put it back in, it still "pops" out and seals around my cervix, seems secure. Well, for another 2-3 hours, that is! If I ignore the leaking, it gets worse and worse, and then I do seem to have an overflow situation? Maybe I need the next size larger Meluna? Thoughts?

Also:
-Nothing in my life has changed (sexual activity, pregnancies, etc)
-Periods are a tiny bit heavier but I'd still classify them as "very light"
-The blood DOES seem to be more watery lately, less clotting.
-I've been doing more physical activity (yoga/walking) and am a bit stronger; could I need a firmer cup due to PF muscles? Or could my cup be softer and not as "firm" due to the years of use/material wearing out?

Can you help me diagnose the problem? I've browsed the "leaking" category, but can't seem to find an answer. I seem to have a very small vaginal opening (I always have a little twinge of pain with removal) and probably a dangling cervix/shortish vagina?

Thanks!