I don’t know what to do after high school?

You can be an artist and have a day job.  If art is what you love but you recognize that you may not earn a living at it, then you can always double major.  Get an art degree as well as a degree in something else.  Then once you get to work, become part of your local art scene (assuming you have one and don't live in a small town).  Get to know people involved in it and make contacts.  Whether you ever make a penny off it or not, you can still enrich your life with art.  

Another thing to think about.  People who fail at being a professional artist usually don't fail at creating art.  They fail at selling it.  So, if you go into business, particularly sales (and I'm not talking about retail sales, or crap like selling cars or insurance, but in the sales department of a business), you'll learn HOW to sell stuff.  And you'll do it while building up a nice portfolio.  Then if you are involved in your local art scene (see previous paragraph), you'll have a better idea of WHO to sell your stuff to. 

Be an Art teacher      

my friend's husband is an "artist" - studied at some college and has a title as a professional artist. he has nevr ever  EVER  sold even one painting during his entire life (in his 60 now) even thou they got some spot at some point and she was schlopping his pictures there every day. still no one wanted to buy any and she was the one sustaining the whole family all their lives. unless u count on finding a rich spouse who wouldn't mind to sustain your art cravings i suggest u get a  REAL profession and do art as a hobby. i do art as a hobby - paint and do ceramic sculptures. as my  HOBBY. unless u get into the stream which means u should be very good with people or have some connections u re not going to make any money on your art. u do not need to study in college to do art projects as a hobby either. 

One of my accounting clients had a rental business which kept her quite busy, but she always considered herself to be an artist.  Painting as a hobby, her works were in smaller NYC galleries several times a year.  She was fairly well-known in the state art community.  She also put on art instructional clinics a few times a year.  Becoming an art critic, and even starting an art-related non-profit organization are other paths one can attempt in the art world.