Deb, Matilda often screamed for hours as well. She had reflux and I would try everything, often I would have her in the sling, bouncing on the fit ball and crying as well. The only advice I have is to breath. Take deep slow breaths and maybe remove yourself from her for a few minutes to do it and restore some peace within you. I found that Matilda settled better if I was able to settle down too. So I would put her in her rocker or pram and strap her in and take a step outside and breath & stretch for a minute, then I would go back in and restart settling her.

Good luck!!