Haha I got the grapefruit cravings too during early pregnancy, sibuk pergi pasar cari yang manis! Week 4 for me was more like a "wait, is this actually happening?" moment because honestly you don't feel much yet lah, but what struck me was how tired I was, like fell asleep during my kids' school run, which never happens! A few of my mum friends said the same thing, so I think that sudden exhaustion is quite real even though you can't see anything yet.