Soreness?

Hi guys! Long time cup user (like 10 years). I recently had a baby and have been back to using my cup for 3 periods now and I feel so sore. I use a soft small saalt cup because I was having this issue with larger cups I tried. I especially am having trouble when I have to poop (without the cup in) that having to bear down to poop is excruciating like I might as well not go. The pain seems to be the pressure of the poop on my vaginal walls? Anyone have any idea what I’m doing wrong? Did ny organs rearrange and my body just not made for this anymore? Do you have an even smaller softer cup you would recommend? Help 😫