Mrs Hon,
Don't worry, i had this experinece before when i carried my daughter, i kept on breeding brown blood, not so seriously just drop on the panty.. last for around 1 - 2 weeks, then it's ok. my mum said this is the last M-blood remained there. Don't worry, but take more rest.
You know I'm now 5week5day, I toke Ultra sound (belly surface type) 5 days ago, my doctor said it's too small that up to 5 week standard, i was a bit upset, but, i immediately consulted and ultra sound (which is "inside" type), the doctor said it's up to standard and very good. I'm so confused as well... anyway, i have nothing to do this, just let it be...