What Causes Stomach Pain After Insertion Of Mirana?

Hi im 21 years old, 5'5" 123 lbs. I just had a child in march and had the Mirana put in place in April. The last two day i have been feeling kinda sick to my stomach. It feels like severe hunger pains but i wont be mentally hungry due to just eating, and or feel like ill just throw it up. Last night i had pain in my abdomen that was right below my sternum that lasted 5 seconds off for 15 then back again. lasted roughly 5 mins! I have kinda had the "stomach flu" Symptoms with diarrhea yesterday. any idea whats wrong with me/