Pregnant? with IUD?

Hey ladies, I have been on the Mirena IUD since April with no problems. The past two weeks I have been having pregnancy symptoms. I know it’s extremely rare to get pregnant but it is possible. I had a very very light period for about 5 days 2 weeks ago, lighter than it normally is. That isn’t two alarming for me because I know your period can go away all together. But I have been having serious symptoms. Breast tenderness, especially my nipples, loss of appetite, bloated, nausea, and I’ve been super crampy in the morning. My boyfriend made the comment “are you pregnant” joking around because I was super crampy yesterday morning and it made me think about it. I bought a pregnancy test last night and it came out negative and that is putting my mind at ease alittle but I just feel like something is off you know? I feel like I’m just being paranoid. What do you think?