My lower stomach is cramping lightly and period is due in 4 days. Usually cramps come just before bleeding, but this started earlier. Did stomach cramps happen before your positive test?
Light cramping can be an early sign yes, its often the implantation or uterus stretching. But cramps happen for many reasons too. If it feels mild its usually fine, just take a test after your missed period.
When I conceived I felt mild cramps very early, kind of like period pain but lighter. I honestly thought my period was coming. So yes it can be an early sign but its not certain, a test confirms it.
Mild cramps can be normal early, but if its strong, one sided or with bleeding, please dont ignore it and see a doctor quickly. I say this from my own experience, better safe.