Transitioning from Tirz…having issues

I am transitioning from 10 mg of tirz to Reta. Did a cold switch (no taper)- just changed dose to 2mg Reta. I plan to be on this dose for a month before moving up if needed. I’m on my second week and experiencing a lot of trapped gas and abdominal cramping. This is something I did not experience on Tirz at all. I’m curious if anybody else has experienced something similar? Particularly interested in those who transitioned from Tirz to Reta. Ty