Looking for alternative IBS-D medication

I’ve had issues with insomnia in the past and my Wellbutrin seems to help with that. I also get butterflies in my stomach/restlessness and I’m starting to think it might be related to the Viberzi since it has opiod receptors. I imagine it feels somewhat like a mild drug withdrawal? It’s incredibly uncomfortable. Just wanna know if anyone else’s experience with Viberzi and if there’s another medication that works better/has less side effects