Sayang, spotting dengan delay macam ni kena check dengan doctor, okay? Bukan boleh guess-guess especially with light cramps. UPT boleh false negative, especially kalau test awal sangat. Please book appointment or drop by clinic/hospital untuk proper checkup, they can do blood test or ultrasound to confirm apa yang happening. Jangan worry dulu, but don't delay lah. One of my mum friends had similar situation and turned out okay, but she went to check right away. You'll feel so much better once doctor confirm. Sending you strength, hun!