It means both, and yes it depends on the context. Yo no creo en el amor-I do not believe in love ¿Iras a la fiesta esta noche? -No creo- - Will you go to the party this night?- I don't think so

Ayúdame* Could be both :V It depends on the context but I think it's more usual to translate it like "I don't believe".

Both!

Depende en que oración lo estés utilizando