Curious about Menstrual Cups

I'm 22 years old and have a 23 month old boy. After I gave birth I put in an IUD. I also Breastfeed which makes my periods irregular, but my periods have been regular lately except when i get my period I bleed like crazy. I use ultra tampons which I have never used before I had my baby. Within an hour or 2 I bleed through the ultra tampon. And it's not just a little bit of blood it's like a gush of blood. I'm curious to know if a menstrual cup would help stop the leakage at least for a while because it's very annoying to have to change my tampon every hour especially when I'm at work. I have to wear a tampon and a heavy overnight pad all day long. 
If you also have a very heavy flow and use a menstural cup, how often do you need to change it?