BFP or Fluke?

Chelsie
Ok, so I typically run a 31 day cycle, I'm now at day 36. Took a First Response gold digital test this morning (I'm not a fan of digital tests, but it was what my husband picked up) with FMU. I had to go really bad so it was a pretty intense flow for the 5 seconds, so it may have over saturated. The test had the solid clock when opened, and blinked while testing. When the test was complete it popped up an error question mark (typical digital 🙄). I let it sit for a minute or two while I popped up good ol' google and read that you can pop open the test to read the strip yourself (I know, shouldn't have done that). I picked up the test to begin disassembling and the window changed from a question mark to a "YES +". Inside, the strip looked like this. Mind you, no more than 5 minutes had passed, and it was far from dry. 
I rushed to the store and got one of my trusty regular first response tests and took it immediately, it was very obviously negative. So I'm thinking I over saturated the test and it was just an evap line or some other fluke? I tried the water rinsing test and it didn't wash away. But I've also read that's a flawed theory. Should I test tomorrow with FMU again or give it up?
I'm never the crazy one and I hate to be that guy, but if I'm not I'm worried about our future TTC attempts, with lack of period and my history of ovarian cysts and endometriosis. So if anyone made it through this long post and has some insight for me, I would really appreciate it. Thanks!