When I drink milk lately. I seem to become gases. What could this be?

Lactose intolerant. It is possible to become intolerant to milk sugar (lactose) at anytime. The best test is just to avoid milk products to see if 'the gas' goes away, then re-challenge and it should return. Another sign of milk intolerance: loose stools. If you are lactose intolerant then you can avoid milk products altogether or drink lactaid milk or take lactaid pills with milk products. Hope you are better!