My guess would be the flax seeds might be the culprit - is there a reason for those particularly? You could try another one without them.I just mixed up a shake with 2 cups of milk, 3 eggs, 2 Tbsps of Ground flax seed, a banana, and 2 big scoops of ice cream w/ 3 Tbsps of sugar. But even this ended up getting me gassy and bloated.
Or possibly the bananas.