Taking probiotics while pregnant

Any of the mommas here taking probiotics? If yes, which ones?

I am currently 26+2 pregnant with twins and I am SUFFERING from gas problems, constipation, I can’t eat anything cuz it’ll upset my stomach so I’m living off of fruits and salads which is driving me insane cuz I’m starving all the time, there’s clearly something wrong with my digestive system. My doctor recommended taking probiotics but never said which ones there’s a million of them, I went to the pharmacy but they refused to give me any of the ones they have cuz it may pass the placenta harm the babies.

I’m really struggling here ladies, any help? 😩

PS: I tried taking Tums and GasX and none of them works