I'm freaking out

OKAY. My husband and I have been TTC #1 for 14 months. I had every procedure done to make sure there weren't any underlying issues- and there isn't. And the hubby checked out good, as well. I took this test yesterday afternoon, 10 DPO and got the result within the 3-5 minutes. I at first thought I had line eyes but I walked back and it was there. BUT I'm posting here because I took a test this AM with FMU and there wasn't a line at all. I've been using the wondfos because I'm the most impatient person in the WORLD! Could this be an Evap even though it appeared in the first 3-5 minutes?! If I WAS pregnant, wouldn't I have seen a line this am, too?!