hi K.,
i totally sympathize with you and went through the exact same thing with my 3 year old. when he was 2, he started using the potty occasionally and never had a problem with #2... then for whatever reason, i believe it was a constipation episode, he associated #2 with pain and stopped going. he would cross his legs, hide, and hold out for days sometimes. we started him on miralax too because the pediatrician recommended it and although i was very skeptical in the beginning, i am now so happy we did it because it was the ONLY way to make sure he would go. he was on it for an entire YEAR. and he had to take an entire capful (sometimes 1 and 1/2) to go everyday. and i dont think he ever went because he wanted to, he just couldnt hold it in any longer... i was up night after night thinking my 3 year old would soon be 8 and on miralax and wearing diapers forever afraid to go #2... and then maybe 4 months before he turned 4, i decided to stop talking about it, when i saw him holding it by crossing his legs i would just make a mental note to up the dosage for tomorrow of miralax, and i gently told him that he would poop in the potty when he was ready whenever that was it didnt matter...just very gently told him he would do it whenever he wanted and it was all okay and acted like it was no big deal. i always encouraged him to pee in the potty two or three times a day (before preschool, baths...) and kept him in diapers (because the miralax made a mess of his bowel movements). anyway long story short after all that agony ONE DAY (and everyone told me this would happen but i didnt believe it) he went pee in the potty and some poop (i think accidentally) came out too and he was SOOOO proud. he said "it didnt hurt!" and from that day on he has no problem going poop and pee and is completely potty trained. that was two months ago and he will be 4 in july. honestly if i had to do it all over again i wished i would have stop stressing, stop talking about it to him and just gently gave him encouragement... i think lots of kids go through this, no one wants to talk about it though because its such a taboo subject, but your little girl WILL go eventually. i hope this helps...! hang in there i know its soooo frustrating!