help please

hi. i’m 16 and i’ve been having these thoughts for a while that i could be bi. i’ve always liked boys and i’ve done stuff with boys, i’ve never found a girl attractive in the sense i’d wanna be with them. i don’t even think i can see myself marrying a girl or even doing stuff with them. but why does my mind keep telling me i am? why do i sometimes get turned on by a girl? why do i sometimes like to watch lesbian porn? does that make me bi? i don’t want to be bi because i know it doesn’t feel right but why can’t my mind stop? it really stresses me out to the point i wanna cry because i don’t want to be bi, i just want to live my life. these thoughts come and go and when they go away i’m perfectly my guy liking self. but when they come i rethink who i’ve always known i am. it’s not that i’m homophobic or my family won’t except me (i know they will) i just don’t know why but i feel deep down that’s not who i’m supposed to be but my brain is telling me something else.