Help baby has bad gas/ constipation

Natasha

My baby girl was born a premie and is about it make a month but she start having really bad gas and constipation, I have tried putting her knees to her chest to help her, I tried bicycle kicks, I tried belly massage, I tried gripe water original, and even tried her er soothe probiotic drops and nothing is working, any ideas to help her? She screams the whole night cause she can’t pass gas and poop