What Could Be Causing My Irregular Periods, Spotting, Nausea, Fatigue, And Irritability?

I’ve been having irregular periods and spotting. My last period was late and I was spotting for almost two weeks before I got it, it ended about two weeks ago. I also used masturbation with a brush handle today and started bleeding a little after but no pain or anything. This sometimes happened before but rarely. I had some nausea a few days ago as well, it was sudden but it might have been because I ate bad food that morning, I’m not sure. I have been feeling tired and easily irritable lately too, for about a week almost. I did have sexual intercourse 1-2 weeks ago and the condom got stuck inside for a few minutes but I was on my period. And I took a home pregnancy test two days ago it was negative. What could be the cause of these symptoms?