Marina IUD

Had the iud since the first of April some time after my daughter was born in 2014. Haven't had a menstrual since. Then all the sudden IV started back having about a month ago and I honestly don't know whats going on. Last month it lasted two weeks then I just started back today and I honestly don't know what's going on. Don't have insurance to go to the doctor. Stresses me more then what I'm already stressed about. Any one else experience this? Cause I am a little worries.