Pregnant????

So I have had a Mirena IUD for a year and always had a period every month. I haven't had any complication or issues with the Mirena IUD. But in July I missed my period, no spotting,no cramps-nothing. I waited a week, took a test and it was negative. I am now a month late, last weekend I went to a wedding and suddenly felt very nauseous, after the ceremony during the reception a lady wearing perfume passed my table and I swear I almost puked right there. So I left the reception, and went to my hotel. On my way in I passed a guy smoking a cigarette, as soon as I smelled that I started gagging. Luckily made it to my room in time to throw up. Once I threw up, I was completely fine and when back to the reception. I took a test this morning and it still says negative. If my period doesn't come on august 10th I'll be 2 months late. Has anyone ever experienced anything like this with the Mirena before? Is it possible I could be pregnant and the tests are showing it?