What brand of sea salt are you using? You might try a different brand - many here use Hymalian, Celtic, or Redmond. You might want to try one of those.
Also, since you aren't following protocol and doing the SWF twice a day, this is cause for some concern to me. I've read on this forum that doing the SWF in the middle of the day is not beneficial because you are washing out any of the lemonade that you have in your system. Doing the SWF in the morning, you are doing it on an empty stomach, so you have nothing to worry about.
Just a couple of my thoughts on the matter. Your body may just react to the salt (or something else). The bloating will most likely go down as soon as you are finished with your fast.
As for the cramping in your stomach - how much cayenne are you using per 10 ounce glass?
Are you putting the cayenne when you pre-mix your drinks in the morning? Cayenne "blooms" as it sits in the liquid and gets hotter!! If you put the cayenne in just before you drink, you should find that you are able to tolerate more and more. I typically start my day 1 with a little less than what the recipe calls for and over the course of the next few days steadily increase to 1/4 tsp. per glass.
I premix my lemonade in the morning so that I can take it to work with me, and I carry around a little jar of cayenne and a measuring spoon.
I hope the next day or so work out better for you! :)