Faint line...keep testing?

So AF is due tomorrow...had a D&C in january due to blighted ovum at 9 weeks and abnormal tissue upon sampling...chemical pregnancy in may...i tested earlier in the week with cheapie it was way negative...i was surprised when i first looked that it wasn’t blaring red because i’ve felt pregnant all week...i just had a feeling...came back to check again within the 3 min window and i believe i see a very faint line?! having a chemical before i’m not going to get my hopes up...should i keep testing to make sure it gets darker?