That is not a good sign.
It sounds much more than just an issue of too much lactose, too soon.
If you can afford it, I'd look into other options. Eggs are pretty cheap for protein and fast but won't match them in carbohydrates and calories.
More food or some sort of mass building product. Yes, yes, I know. Then again most of those will have whey or milk protein in them which it doesn't sound like your body likes.