Unsucsessful flushing

I did my first flush about six weeks ago and passed about 50 stones which included some large and a lot of chaff. My problem is that I have done the flush about four times since as I was feeling so unwell and can't seem to get anymore stones out. Just passing a little chaff. I had an ultrasound and I am very congested with stones and Feel that I may be so jam packed that I have waited until it's too late. I'm taking parasite tablets,don't think thats the problem. I'm trying to keep a very positive attitude about this as I am nursing a son who almost died from infection due to surgery and I consider going under the knife as a last resort. Is there anyone out there who has had an experience like mine that can encourage me to keep going.
I was told by my radiographer that I am a prime candidate for infection or gange grene at this stage.