With kidneys that are fully functioning the baby can swallow amniotic fluid and excrete it as urine. The amniotic fluid is completely replaced every 3 hours, so the baby's environment stays fresh. Even though she is not eating yet, the baby's intestines are contracting in peristaltic movements as if she were digesting food. Even if that combo still sounds disgusting, many women do experience food cravings. As long as they are not harmful go ahead and give in to them in a moderate way.
Some women do crave harmful things like kerosene, clay, starch, ice or nail polish.
This is a disorder known as pica and should be discussed with your caregiver. Since you are really beginning to show, the subject of stretch marks will come up. You may or may not get them. This has far more to do with your genetic heritage than whether or not you use an expensive anti-stretch mark cream. The veins on your breasts are probably much more noticeable and your nipples darker in color.