i have read that to feed as a vampire i have to use "e" on a sleeping npc but when ever i do this it either wakes them up or when i am sneaking i end up pick pocketing them

what am i doing wrong?

If the menu isn't appaearing, then look at the mouse icon when you look at their body. Is it different? If it is, then I have no idea, because a menu is meant to appear when you interact with them.

If the icon is not different, then you are not a vampire.

the icon when i am sneaking turns to a pickpocket icon and when im standing its the normal speak one
i am a vampire because no one will talk to me and instead says things like "say away from me you beast!"
(not exactly that i know but things like that)

maybe you can't feed because you've already fed enough? I don't know if that's how it works or not but it's worth a try. Wait (inside!) a few days then try again.

You might of experienced a bug where you aren't actually a vampire, but people recognise you as one. Check your Buffs/Debuffs menu and can you see vamparisim as one of the buffs? or a debuff for sunlight damage?