Bfp on 5dpo?!?!

OK so I know you cant get a bpf on 5dpo but I was like, oh hey I'll do one for the heck of it just for laughs... Only now I'm not laughing... I'm freaking out. No I was not pregnant before. We are using donor sperm. No I have not cheated. DH has had a vasectomy years back when he was with his ex wife. I felt myself ovulate Sunday night donor came over Monday morning... Its now Friday. Any explanations???? The top one I took first and the bottom I took next after seeing it and started freaking out. And there is a smudge next to the line on the bottom line but you can still see it.