Formal dress and dad

So I just got home from spending the night at my grandparents and I got my formal dress yesterday. I come home and my dad just barely sees my dress in the bag and says "What the f$&k Is that" my dress has a slit in it to a little above my knee, has a cut out back and a sliver of the belly cut out. Well, I'm on my period and today has already been an emotional day so I went to my room and currently crying. I feel like such a disgusting person now and don't even wanna go to the dance. I just went to the kitchen to get something to drink and told my dad thank you for the drink. All he did was give me a face and sighed like he hated my guts. I'm so upset and don't know what to do.