Mirena IUD...pregnant?

Hey ladies (and gentlemen). I have the Mirena IUD, have had for almost a year. I am currently having light bleeding and had some strong cramping a few days ago, and I just had my period a little over two weeks ago, but I have always been really irregular so I wouldn't be surprised to be having my period again now.

However, for the past 4 days I have been puking every morning and evening, as well as having some diarrhea and feeling very fatigued. I used to smoke, and now the smell of cigs is very disgusting...I used to drink only water and now it makes me gag, as does brushing my teeth. I wanted to think it was food poisoning or a virus, but my son and partner have eaten all the same things I have and have been kissing me and drinking after me, and they are not vomiting or feeling bad at all.

I get nervous because I was on the pill, no skipping or anti-biotics or other no-nos, when I got pregnant with my son. And I also had a period my first month of pregnancy with him, and I began vomiting about 2 weeks before I got a positive on an "early result" test (doc confirmed I was 6 weeks pregnant at that time). I POAS yesterday and it was negative, but as you can probably tell I'm still nervous.

Any ideas?