try palpating her. As you are handling her, wait until you can feel her muscles are loose and in a relaxed state. Allow her to crawl forward onto something while letting her glide through your hand, through the space between your thumb and index finger. With your thumb on her back and your index finger under her belly, apply very gentle even pressure upwards with your index finger cupped around her underbelly as she glides through your hand. She has to be relaxed and moving forward in a steady motion for it to work or she will be too tense to feel anything. It usually just takes a few tries, but if you do it right you'll be able to feel a distinct little "bump bump bump bump" in her lower abdomen as she is moving forward. If you can't feel that, then she's likely not gravid, especially if you think she's already showing a bit. If you can feel that... it's not poop you are feeling