Insertion was horribly painful, I have no children so the best wa...

Insertion was horribly painful, I have no children so the best way to describe the pain is to compare it with my worst period cramps ever, although far worse. And for the next 3 months thereafter I had pain and I guess like swelling or bloating in my lower abdomen, which was so bad I felt dizzy and had to grit my teeth until it passed. (I still feel like this but now only on the very rare occasion near my period.) Naturally I had no desire for sex during this time, and afterwards my libido was present for about 2 weeks....but it's COMPLETELY gone now and haven't seen it since ...I don't know what to say to my BF to make him feel better about it or how to explain it and he doesn't want me to take it out .... I don't want this damn thing to ruin my relationship. On top of that my periods are worse; my cramps are more intense and last for days now not just 24hours and my breasts hurt so bad and are so swollen and hard my nipples are like daggers and it hurts to touch them. I can't be sure if I put on Mirena weight or just a winter 10lbs? It's convenient.... but I'm not sure it's worth it??