My advice to you would be to spend your first year at university doing a wide range of courses so that you will know what you like. I don't want to sound patronising but you are very young and will almost certainly find new things which interest you. In fact you should be open to being exposed to new things, since limiting yourself to what sounds good now will mean you don't expand your horizons as much as you might.
I'm not sure how the university system works over there, but here you can change your degree pretty much whenever you like. So take a few different things and see where you go with them.
Basically, based on what you've said, you are interested in how it is that we as human beings come to understand the world, right?
My advice would be to take philosophy for the metaphysics, psychology for the individual perspective, sociology or anthropology for a broader social perspective, and then something different, maybe history, maybe neuroscience, maybe a language, maybe art history or something like that.
I don't think you should be considering careers right now. There are no careers in philosophy unless you want to be an academic. If you are interested in drugs (which is fine, although you will almost certainly get 'over the drug thing', most people do) then you might find you have to do some difficult and highly abstract chemistry and biology before you can do research into things that interest you (a journey of years). There are no courses which are about drugs and how they influence your spirituality. That doesn't get taught at university. Probably the most common question on this board is 'how can I do research about drugs' from people who don't realise that studying organic chemistry, biology, neuroscience, and all that doesn't constitute a spiritual psychoactive journey, it constitutes years of very difficult science being taught by people who don't give a shit about getting high and expanding your mind.
So do some general stuff and see where life takes you.