possible chemical pregnancy?

So, i am a total weirdo and i keep my tests incase i want to do a line progression. Well i looked at the one i took yesterday today and it was really positive. I started late last night, could i have had a chemical? I have never heard of positive evaps. Either way there is no baby sadly. Just wish i knew what exactly happen, i only looked at the test for a second and walked of so i have no clue if it was positive before i looked at it again. Thanks for anything you guys know. I know not to trust outside of the time frame also af came so there is no concern for a current pregnancy.