Gallstone attacks are over in a few hours, because that's how long it takes for an expelled gallstone to work its way painfully out of your body (the gallstones are wider than the ducts they travel through). If they go on for days then that means that a gallstone has got stuck and caused an infection. This is why you have to go to hospital if the attack lasts for more than 12 hours, because then it's probably more serious. As far as I'm aware, that's universally true. Short of having emergency surgery where the surgeon also keeps the gallstones to show you later, you never get to see the gallstone, you don't know how big it is and whether or not it involved sludge. So if your attacks went on for days, and you weren't being hospitalised with an acute infection, I strongly suspect that they weren't gallstone attacks at all. What symptoms did you get, out of curiosity? How severe was the pain?
Yes, I presume there are some people who have silent gallstones and other issues which mimic a gallstone attack, while there are others who have active gallstones as well as other issues, so that both are causing problems. I found that once I had experienced a gallstone attack, it was obvious when another one occurred, mainly due to the intensity of the pain; before I had suffered an attack and been given a diagnosis, I wouldn't have had a clue. With other types of abdominal pain I've had, I haven't been quite sure what was happening, and I'm fairly sure that I have muddled up intestinal pain with menstrual cramps on some occasions, and muddled up intestinal pain with bladder pain on other occasions. I definitely remember my GP palpating my abdomen when I was reporting what I took to be intestinal pain, and her saying, "Actually, that's your bladder." So I think that it's very easy to misinterpret abdominal pain.
My first gallstone attack should have been blindingly easy to diagnose by the emergency doctor who came out to see me in the middle of the night: excruciating pain in the upper right quadrant which had me curled up in a ball unable to move, substantial hypothermia, nausea, occurred a few hours after eating a fatty meal. Yet he didn't even examine my abdomen properly, failed to take my temperature correctly, and made vague noises about "probably a virus". Thankfully the GP who saw me the next time I was having an attack was a better doctor, spotted the problem immediately, and sent me for an ultrasound to confirm it. I dread to think of how much misdiagnosing is going on in this area.