Help me I'm going crazy (potty training)

My daugter is 2 getting ready to be 3 in May,  We have been doing the potty training for the last year and I can not get my daughter to poop in the potty.  She will poop in her pantys and stay in it.  This sounds gross but this is what i go through 3 times a day. She will put her pantys up her butt so we won't see that she has pooped and I keep telling her we all smell it.  I tried the diapers and she will make 1 small little poop and cry and cry to get it off of her.  She tinkles in her panties but that has slowed down alot.  the pooping is what I have no idea what to do?  I tried stickers!(that worked on my son) .  Can u please help me out.  I have asked everyone else and they have no idea.