help put my mind at ease

I got the skyla iud a little over 6 months ago and I have yet to get my period this month. This makes me nervous because I have gotten pregnant in the past and I definitely don't want that right now. I took a pregnancy test and it came back negative but because of the iud I heard that it could be ectopic and not show up on a home pregnancy test and that I'd need to go to the doctor for a blood test. I just need to know if I'm freaking out for nothing or if I should be genuinely concerned