Hay, totally understandable ang takot mo, lalo na kaya lang six weeks! Honestly, kahit breastfeeding, hindi 100% safe from pregnancy kaya if you're not ready for baby number two, mas maganda na mag-discuss kayo ng partner about proper contraception, maraming options na safe while breastfeeding like pills, IUD, or condoms, and your OB can guide you best on what's safest for inyo. A few of us went through the same worry, at yung peace of mind talaga worth it once may proper plan na, so please don't hesitate to ask your doctor ASAP!