It is possible she received too much attention when she previously had these accidents! Not that you meant to 'train' her to poop in the house, but what can happen is if we spend more time paying attention to negative or inappropriate behavior instead of positive or appropriate behavior, the dog will offer the wrong behaviors! Example - say she pooped in the house and you caught her in the act. Like any owner, you probably shouted "No! Don't do that! blah blah blah...
" She's NOT thinking oops I pooped in the house - she's thinking more like "cool - look at all the attention I'm getting for pooping in the house!" See how this can get the wrong results? It's not that telling her "NO!" was incorrect - it's what you do immediately afterwards that makes the difference. Whenever you discipline, you need to follow through by immediately
showing her what behavior is correct. So in this example it would go something like "NO! Bad girl!" - then taking her outside. If you are lucky enough for her to potty again while you are with her outside, you would praise her like no tomorrow and reward her also. Yet, like most dogs, once they poop they are good to go for several more hours. So the best scenario is to make her succeed, not fail, when she's in the house. You would do this by restricting her access to areas of the house you cannot supervise her; keep her tied to a leash and tie it to one of your belt loops so she has to go where you go (this has other great benefits in dog training too). That way, if you see her acting like she has to go - you can immediately take her outside and be able to praise and reward her when she does go.
Another thing to keep in mind - dog's tend to live in the 'second' when it comes to what they are doing. If she poops in the house, and you find it later (and later means anytime after 3 seconds) she cannot put two and two together if you bring her to it and discipline then. All she knows is you are dragging her over to her poop because of some 'unknown' reason - but not because she made a mistake. Keep this in mind for any time you find she was a naughty girl!
It's really easy for us to put human emotions or tendencies onto our dogs characteristics, but they really don't have that abililty to 'feel' or 'reason' in their brain like we do. So she may have appeared to feel bad or show remorse on what she did - but it's more likely she was reacting to your voice tone and body posture at that time.
Curing the poop problem is actually easier than curing a pee problem in the house. The reason is dogs are very very regular. If you feed her scheduled meals, to aid in her body keeping the regularity, and you actually wrote down the times of the day she poops, you'll be amazed how close to the minute how regular she will become! Kind of weird keeping a poop journal but it works! With regular meals of a quality food, limiting access to her surroundings during this housebreaking re-training, and using immediate timing in your discipline and praise - you should be in the clear within the next two weeks (at the most).