Congratulations on baby number 2! Sakit pinggang dan cramp tu memang biasa dalam early pregnancy, especially since you haven't had a pregnancy in 10 years, hormones and ligaments are starting to shift lagi, tapi memang best to get it checked at your scan nanti just to be sure everything's progressing well. A few of my mum friends juga complained about this around 5-6 weeks, and it settled once they got their first scan and everything was confirmed okay. In the meantime, try rest, warm compress, and maybe take it easy with heavy lifting since you already have a 10-year-old running around! But do mention all this to your doctor at your appointment, okay, jangan tunggu.