!!HELP..LONG DISTANCE RELATIONSHIP!!?

hi u guys well im 16 years old and alittle more than a month ago my bf left to his country but he is ing back in december...recently wen weve been talkin its almost always been bout weed n drinkin and him gettin into trouble..he is also 16...i luv him so much n wen he was here he was the perfect bf u can imagine!! really he was a sweetheart always wanted to be with me...he was just perfect..he wwas the first to remember our one month and i had forgotten i feel bad for that..but i need sum help..he forgot our 5 months today..he thought it was tomorrow..n idk i feel him different...do u guys think that smokin and drinkin is affecting him..he always talks bout that..i dont think he cud forget bout me that fast and any of u guys been through sumthin like this..n also wen i tell him that he makes me feel bad sumtimes he thinks im mad and says he doesnt want to talk to me wen im mad...i trust he is not doin anything w/another girl...n i wanna help him..wat can i do ADVICE PLZ!!