What Are The Side Effects Of Mirena IUD?

I was on the Mirena birth control. I went off it May 3rd and we had unprotected sex May 26th and May 31st. I don't know how long my cycle is because I have been on mirena for so long that I lost my period. Anyway, I had pregnancy like symptoms for a week and now i am cramping pretty bad but only having very light brown spotting with the occasional pinkish red spotting in there, mainly when I wipe. Not even enough for a pad or tampon but just enough for a liner. Am I pregnant? The cramping is bad enough I had to take Midol and Tylenol. But its been so long since I've had my period I don't know if this is what would be considered a normal cycle for me. Should I test? Or should I wait a week longer? Do you think I am pregnant?