This is year I had a few new teachers so I informed them that I go by Shaun but  my teachers from last year call me _____. All of my teachers refer to me with female pronouns.
How do I ask my teachers to refer to me as he? It seems kinda akward to do and they might question me on why.

As a parent....my suggestion is...get your parents involved...however, I don't know if your out to your parents.  I have found that when I went in to the schools and advocated for my kid they got the results they wanted.  Often times they had tried to advocate for themselves but were unsuccessful. 

If you can't get your parents involved then I suggest you go to your school counselor and talk with them and have them help you find a solution.  They might be willing to educate staff members.

I recommend writing a letter/email explaining everything and how important it is.  Most people just don't know the right protocol.