Waalaikumassalam! Sayang, since you're 18 days late and worried, please see your doctor or go to the clinic ASAP , they can do a blood test which is much more accurate than home tests, and they'll help figure out what's happening. Don't start any jamu yet until you know for sure, okay? A few of my mum friends had late periods from stress or hormonal changes, but some cases memang need proper checking. Better safe than sorry, especially if you're uncertain about the pregnancy test result. Go get it confirmed, then you'll know exactly what to do next. Jangan risau sangat dulu, doctors see this all the time!