Gallbladder problems after nissen fundoplication or dumping syndrome?

So I had Nissen fundoplication in June 2018. It is now November 19th. After the surgery I would get bad diarrhea if I ate too much, too fast, or something challenging (like soda and salad). So I adjusted my diet and the way I eat and everything was going okay until about 2 and a half weeks ago.
Now everytime I eat I get gut wrenching cramps like someone is stabbing me and twisting my guts. I then break out in a cold sweat. The pain is so bad I get nauseous and cant even walk or move. Sometimes I will get diarrhea along with the cramping but the pain doesnt go away after I have it like it used to. The cramps will stop after about 3 minutes then start up again in 5-10 minutes. My stomach feels sore and gurgle for hours after the episodes.
My coworker gave me some bentyl (a stomach relaxer) and it has totally saved me! So I called the dr. And he wrote me a script but said he wants me to come in for an ultrasound on my gallbladder. I cant get that done right now because my insurance won't start till 1/1/19.
Has anyone else had gallbladder problems after surgery? I thought it was dumping syndrome but perhaps not? Does dumping syndrome cause that much pain? As soon as the pill wears off it's back to pain. Fatty food does make it worse I've noticed.

Hi Kellbell, while I have not had your type of surgery, I did have gallbladder issues. My symptoms started out with pain, diarrhea & sometimes vomiting. It really became severe if I ate anything fried, dairy & high fat foods. Back then I did not eat much of anything fried, once in awhile we went to a place & had fish. I always got sick but I cratered & ate it anyway. When I finally went to the dr they did a scan, I did not have any gallstones. This is the first thing they look for. The next test was a HIDA Scan, this test shows how your gallbladder functions, mine was not working well & had it taken out. They warned me on this test, if it was my gallbladder, the stuff they gave me to drink would probably cause an attack & it did.

For now I would stay away from high fat & anything fried or greasy & see how you do. Bentyl is an antispasmodic. Glad it's giving you some relief.