Yes I remember needing to burp a lot more than usual, but my doc had prepared me for this explaining how tiny the new stomach did not have the space to allow swallowed air to comfortably and slowly be absorbed. With the new tiny sleeve, normal air ingested during swallowing can have an immediate & discomforting effect, and even bring food back up with it especially if laying down too soon after eating. Being vertical is almost required now for burps.
I can distinctly remembering really trying to swallow little bitty swallows in effort to not swallow air. You certainly don't have any residual gas from surgery at this point. Just take it slow, take micro swallows of stuff - and when you feel a burp bubble forming up just give it the time it needs to get out before you swallow anything else.