Help me please

I have been stressed with stuff going on with my car,life,job,and with the father of my child let me start with that first. I had sex on the 8th of this month and according to the app I was not ovulating I was supposed to start my period the 17 but here I am as of now 4 days late. I took a test today but it said negative (it was a pink dye test if that helps any) what should I do?? Could I be pregnant?? I really don’t want to be I have an almost 8 month old I am not ready for another child especially right now.