Suggest Treatment For Uterus Cramping And Low Back Pain

I have had Mirena in for 8 months. I still have periods. Although I am having uterus cramping, constant low back pain with flare ups followed by abdominal cramping all day yesterday, better today on the cramping, but still low back pain constantly. I definitely have a tummy that has appeared over the last two weeks that is somewhat firm and my breasts are sore and big. I have taken a home pregnancy test (negative) but not within the 5 days of a missed/expected period. I am also tired and suddenly can be emotional/sentimental. My period is 1.5 weeks away. Could i be pregnant or are these just more crazy mirena symptoms? I have an appointment next week to talk about taking mirena out and make sure it is even in the right place as I can not feel the strings. age 33, wt 193, ht 5'9". 2 children(ages 34 months and 10 months)