Iud and bleeding

I got the Mirena iud inserted April 13 and the two days after that I was spotting then ever since that I have had a medium to heavy flow. It's now April 28 and I don't know what to do. Has anyone experienced this ? Does it get better or should I get it removed because I've been bleeding for about 15 days now and it's really starting to worry me. Plus there are cramps at times that are just uncomfortable. By the way I know I'm not pregnant hence no miscarriage is happening.