Need help ?? Somebody tell me something

So I calculated on the first response web site from the day of my last period when I was able to test and it said today ! 😏 my period is due on the 28th ! ( 6/28 ) and so far when I took a test this morning which was a clear blue digital it said NOT pregnant !? I don't know if maybe it was just because a lot of people recommend first response and maybe its still to early but idk what I should do ! Should I try testing with a first response in the morning ? Tomorrow