late period

hello so i am 10 days late and starting to freak out. the last time i had sex was may 15th and my period was supposed to come on the 18th. we always use condoms and he pulls out as well. my period isn’t always on time but never this late. I have taken 2 pregnancy test one a week ago and one today, both are negative. a couple of days ago i noticed my discharge was slightly darker as it does this before my period starts. this lasted about 2 days but now its back to normal. i’m not really sure what to do and im freaking out. any advice?