I need help

My period is 24 days late. I had sex January 10th. He wore a condom and didn’t finish. I’m not on any other form of birth control. I took an at home pregnancy test that was negative at 21 days late. Is that too late for that test to be accurate?

My only other symptom other than my missed period is stretch marks, but I could have those as I am a bigger built girl to begin with and have stretch marks anyway.

I’m 18, totally not ready to have a baby or think about being pregnant. I’m finishing out my senior year and I just can’t do this. I’m freaking out so bad and I need help, I’m having the worst anxiety attack of my entire life right now and I need words of encouragement.