Faint positive that faded into a negitive?

I am about 10 dpo and just decided to test because why not? It wasn't fmu. It was 3 cups of coffee worth of urine lol but I took the test and watched the dye move all the way up. At first I seen the FAINTEST pink line at bout 3 min mark, had a mini panic attack, threw the test under the sink, and jumped in the shower lol. Got out of the shower and its as negative as it gets. When I stand by some natural light I can maaaaybe see a shadow of something. But wont show up when I shine a flash light on it or take a pic. Help!