Should I take a test?

I have had the skyla iud for a year and a half and havent had a reall period in a year. I have two days of spotting every now and then.

Recently I got back with my child's father and we have had sex everyday for about 2 months(honeymoon stage or What ever). I got sick about 4-5 days ago and it's not seeming to go away, I've had on and off cramping, no bleeding, VERY sore boobs. I feel tired all the time, and nauseous at random things. I took a pregnancy test last week and it was negative. Should I take another one or stop worrying