A.C.
There are two things you can do while pregnant that should bring you relief and will be okay with baby.
The first is to make a flaxseed tea that will calm down any inflammation you might have.
Ingredients:
1 Tablespoon ground flaxseed
2-2.5 cups of water
Put into a pan and boil together on the stove for 10 minutes.
Take off heat and strain the water from the flaxseed with a piece of cheesecloth or other fine cloth. (the flaxseed will have become glutinous from the water).
Drink the flaxseed tea while still hot/warm. The water will have a pleasant, nutty flavor to it.
I did this tea myself earlier this spring when I was having a gallbladder attack myself. It worked really, really well. So well, in fact, that I only needed to do it once! You might find you will need to take it in the morning and at night. But you should find some instant relief.
Once you have found relief and the gallbladder has calmed down, I'd then go into maintenance mode.
Another trick to do (what I call maintenance mode)--and if you're having issues with your gallbladder/kidneys already early in your pregnancy, I would definitely do this during your entire pregnancy--and even for a bit afterwards--is drink a daily cup of lemon tea.
When you get up in the morning and before eating breakfast, set a coffee pot of water to boiling. Put 2 teaspoons of real lemon juice into a cup, pour hot water into it, and drink/sip it like it's a lemon tea. This lemon water will detox your body (specifically, the liver, kidneys, and gallbladder) and will help against forming any stones--which is what you need to watch out for, now that you do have gallbladder sludge (which means there's something off in the gallbladder/liver) as well as being pregnant.
I've been taking daily lemon water for the past 3 months now and have had absolutely no more issues or pain from my gallbladder. Since it's easy and economical to do, I plan to keep taking hot lemon tea for life, as gallbladder disease runs in my family. I might as well take any temptation away for my body to form any stones.
You will likely find that by drinking flaxseed and lemon teas and adjusting the types of food you eat (so they don't aggravate your inflammed gallbladder) that you will be able to SAVE your gallbladder. You have a gallbladder for a reason; it's best to try to save it if at all possible.