Positive pregnancy test

Hi all, I took a test today knowing I want some Champs tonight 🥂Not expecting any clue, I got a very faint positive line. One I didn’t see last month so I know it’s there!!! Wow. But as I try not to get excited and don’t believe it because I am scared if it is false, I wonder and ask you, have you tested before your assumed period (I should start tomorrow as always on CD26) during your 2WW? Did your test read positive and later change negative? I had an HCG shot 12/18 CD12, 1000 units. Could this be real of fake???