Should I be concerned?

Hello ladies,

I’ve had the IUD for almost 5 years, itll be 5 years in February. Ever since I had the IUD I had a period, it wasnt as heavy as before the IUD but it still would be the length of about 7 days. I still had PMS symptoms as well & I always crave sweets and cramp around my period time. What worries me is I havent had my period in 3 months, the last normal period I had was in September. I spotted in October for 5 days and 1 day being a little lite flow. November I spotted even lighter for only 3 days. December I am over a week late no spotting & none of my usual period symptoms have come. I took a few pregnancy test back in early/mid November & nothing. I saw a vvvfl on 2 test but others I took after that was negative. I went to the doctors & they refused to do a blood test because of the fact I had a IUD saying it was normal. But not having my period isnt normal for me. They did the urine which came back negative. But that was late November I went and I still have no period. Im not sure whats going on but should I be concerned?

I have the mirena IUD & I also have a brain condition that effects my hormones so I told the doctor a blood test would make me personally feel better but they still refused.