Don't trust on 驗孕捧. Sometimes it cannot detect on special case.
Just want to share my experience. My M was late for a week and had little bleeding for 4 days. I checked with 驗孕捧. Negative. But I checked with the doctor was positive. I remembered that my urine was orange (mixed with blood).
My baby was not stable at that moment, so it's difficult to tell her condition. The doctor said maybe it was 宮外孕. I waited for 2 more weeks to confirm my baby's inside. Luckily she was safe and now she's 19 months.
If you are not sure, go to see the doctor. Your baby and your health are much more important.