Some of the best advice I ever got while trying to potty train my daughter was that its a process. That she would go three steps forward and then two steps backwards, and its TRUE! My daughter would do fabulously for a while and then would stop and would actually go back to having accidents or even wanting to wear diapers instead of training pants. So, what you going through is normal.
Work with her. If she was having a difficult time going poop, like if she was constipated, then it may be a scary thing for her now. Keep encouraging her to go in the potty or at least to go into the bathroom when she has to go. I know you probably know this already, but don't shame her or scold her for any accidents she has.
I don't know if you want to go as far as I did, but at one point, I had to put my daughter back in diapers. She had a tantrum while on the big potty one day and fell in. Needless to say, she refused to get back on after that. Potty training stalled entirely. So, she wore diapers until she was willing to sit on her little potty again. It was frustrating and disappointing, but she did eventually get the hang of it all and seldom has accidents now.