Blackmailed into sex

I need help, and I don't know who else to go to. So this guy that I used to go to is now blackmailing me of a sex tape that he made of me. I didn't want him to tape me but he kept telling me to shut up and continue so eventually I just did. Back up a few steps... we would make a trade, sex for drugs... anyways I stopped smoking and he wasnt treating me nicely so I finally pulled up the strength to not see him anymore, but now he is blackmailing me into sleeping with him or else he is going to post the videos of me and him having sex (my face is clearly visible). Idk to do, and I def don't want to sleep with him anymore, but I also don't want to be publicly humiliated. I could go to the police but then again I've been smoking and I'm only 18 so I might get in trouble (he is 20) anyways I need help ASAP bc he is getting impatient, please help thanks.

UPDATE: I went to the police and talked about the evidence I have (photos,videos,messages) and they said they could charge him and have a case, but now I’m hesitant about the police seeing my videos bc well I’m naked and it’s embarrassing. I talked with a detective and he said that a little bit of weed doesnt matter and I can’t get in trouble for that but I’m still not sure if it’s even worth it now bc they said it could be take up to a year to convict and I’m just starting to get my life together again but the guy won’t stop messaging me time to time sending me the videos and photos reminding me of what he has. I don’t know what I want or what to do. I just need some direction please.