I would guess it might be the size issue too. It is a bit difficult to know what is right for you when you can't try before you buy! Plus it is a bit of an expensive mistake to make if you do get the wrong size. I found I needed a smaller size after starting with a lunette last year after an outlay of about $50. I had to remove the stem completely but found that I could still feel the cup when in place and was often really uncomfy when sitting. Some times were worse than others and I found that it was worse as time went on (so I've realised I have had to do some serious work on my pelvic floor ) I never felt any bowel pressure with mine though.

I love the idea of the cup though and when the lunette worked, it was so awesome so I decided to give another brand a go and after a little research, went with the Me Luna. I ended up with a smaller size and the soft cup and so far it has been perfect. So, I guess I am another of the exceptions to the post baby post 30 rule. A smaller cup was best for me.