Pessary ring causing poop issues

I am in the 2 week trial period with a pessary ring. I am in between 2 sizes. Originally had smaller size but it was pushing on rectum and hard to poop; removed that ring. Larger size was placed by Urogynecologist yesterday. This larger size also pushes back on rectum, making pooping more difficult.

Is this normal? I have a diagnosed cystocele and uterine prolapse. I don't think straining to go to the bathroom is wise right now.

I have additional appts with OBGYN to discuss fibroids/cysts so this appears to be a short-term solution until surgery