Help!!!!!

So, I’m having sex with this guy and we don’t use protection. I’m not on birth control, I was on the Depo shot but got off of it in March. Me and this guy have been messing around for probably about a month now, I took a pregnancy test about a week and a half ago, it was negative, recently my breasts have been tender, today I got this major cramp that won’t go away, I’m nauseous, and I have frequent headaches. I know I should take another pregnancy test, but I’m really scared to find out if it’s positive or not. Could the first test I took given me a false negative? I know I should’ve used protection or I wouldn’t be so worried, so I know I’ve made a mistake, I don’t need any negative comments towards this...thanks.