Oh, hun!!! I couldn't read through the last paragraph bc it all just sounded to painful to read and so familiar.
When my lo was born, she was incredibly calm and peaceful. She slept so soundly that nothing could wake her. Fast forward to 2 months and it was like somebody handed me a different baby.
I had NO idea what was going on until the ladies here on BW suggested acid reflux. I had tried everything - colic calm, gas drops, feeding whilst laying down, elevating the cot..
I was put on ranitidine as well. It made things better for a day or two, but then made it worse as ranitidine made her very drowsy and she would scream with any outside stimulation.
PPIs worked. It took a week and half for the acid to stop burning her esophagus and then took time to heal. Like Eloyse suggested, could you get a PPI in the meantime?
*hugs* It IS tough. Reflux is absolutely hard...

We're here for you.