There’s a very low chance of showing positive at 8dpo. I got a negative at 16dpo when I was pregnant with my son (though that’s also not highly common). I’d say 12dpo is a good time to test - personally I wait until the day my period should start. Otherwise I drive myself crazy.

8 dpo is too early to test. Just wait until the day your period is due, or until you miss it. I got negatives up till 11dpo and then a very bold positive the day my period was due. It's honestly not worth wasting the tests to do it early.