The roughage with the romaine lettuce might be harder for you to digest. Put some lettuce in a blender with some water and make a juice out of it. Drink the juice on a empty stomach. This might be a lot easier to digest.
Sounds like you might be sensitive to sulfur. I have trouble with too much sulfur as well. Seems to cause bad detox reactions.Sulfur can be in eggs,garlic, cruciferous veggies, some in sea salt etc...