when to test?

Kate
So AF has been varying between 28-34 days recently I'm on CD 28 and I feel bloated nauseous and a little heart burn. I just don't know when to test with that, should I wait until next week or should I test now I'm also about 12/13 DPO so i don't know if that plays a factor 
Tried to take a CBD yesterday and it was invalid, came up as a book as the result so