My cycle was already wacky before starting IP - I'm just at that time of life...
Anyhow, I have been having issues with the really heavy flow, and my doc put me on a med called Lysteda about a year ago, which reduced it by quite a bit. Might be something to ask about. You only take it when you are having a period - not an every day med.
Also - STOP IF YOU ARE SQUEAMISH - you might try a menstrual cup, rather than other feminine products. My cup holds a lot more flow than the "ultra" tampon, so I can go much longer without having to deal with it and don't worry so much about overflow. May not be for everyone, but I also like the idea that it produces no waste. There is some good info here
http://menstrualcupinfo.wordpress.com/.
Sorry if TMI, but both of these things have been very helpful for me!