If it is colic, the general rule is that the faster you treat it, the smaller the bill. To me, some of the symptoms (spit, wee) don't match my understanding of colic. Maybe a problem with her teats (an infection??). In any case, if it was my horse, I would call a vet out now. I don't like vet...
You've changed so many things it is hard to know what is attracting her: hay, bedding to eat (often done if straw), bedding to lay on, shelter...
I guess the first step might be to see what is attracting her. Does she still come back if you remove the hay nets? How about if you change to an...