I Don't Know What To Do

I have known my bf for around 5 years and we recently just started going out, I do love him we have been through alot together. I have met his family and I love them but I dont know if I have the same feelings as he dose for me anymore. He is going to fast and he says if he ever looses me(break up) he will die and that puts more pressure cause I dont want to loose him but I dont know if i can do all this bf/gf thing and I dont want him to go back to doing drugs and become more depressed I dont know wat to do ):
any advice??