Please help with ex's threats?

Ok so... here's the rundown. Me and my ex broke up 2 weeks ago. We had been together for almost 8 months. Well... he was my first kiss, my first french kiss and... he tricked me into what I guess is called "dry sex" and I had accidently touched his.. you know... because I thought I was rubbin his leg.. and it wasn't his leg... well... he hates me now because I sent a text to him telling him to stop contacting me... he went all stalkerish on me then sent a text saying "maybe I should tell your mommy all the dirty things we did"... if she found out she'd disown me... I don't know what to do... I can't tell anyone because my friends would hate me.... even though half my class are already non-virgins... I'm still a virgin but.. I SO regret doing those nasty things... and when I hear one of my friends talk about how she's a half virgin cuz of her dry sex I feel so nasty... and well... im worried because my brothers going to be talking to him tomarrow because he threatened me... please help... my life was perfect until that jerk... how can I just... keep it a secret... deny it? HELP PLEASE