I have a similar experience, but it is more predatory and "immoral" then yours.
Essentially, I too had a calling to blood magic, however it came from more a feeling of bloodlust. There's this strange, powerful, but dark and violent attractiveness about blood. If you are familiar with the hermetic cosmology, I believe that this spiritual quality/emotion comes from the negative/infernal water element.
But anyways, this bloodlust compelled me to practice some forms of vampirism and blood magic(although it also expressed itself in extreme violence and lust for even more violence).
For you, it may be something similar, or maybe not. Do you feel that this feeling you have is coming more from just intuition? Or is it more emotional and spiritual? Is it more like an inspiration from an unknown source, or personal desire?
If it is more like your intuition, or more like a strange inspiration that you aren't sure where it comes from, it may be your spirit or higher self trying to get you into it for whatever reason. If it is more emotional feeling, and more personal desire, than it is probably more like what I had, and is the expression of a dark spiritual quality within you.
A lot of the things you mention, sound like your mind/subconscious honing in on blood, kind of like how a psion may get in tune with psychic energy.
And ultimately, the decision is yours. You are your own person, and may do as you wish. If you truly wish to get into it, than do so. One of the worst things you can do in life is throw away your own desires out of fear others may not approve. However, if you don't want to, then thats on you too

It is up to you to meditate on it, and reflect whether it is a true desire, or something you do not want.
Anyways we aren't the morality police
