For some people, seeing a psychiatrist or psychologist is a sign of weakness. It is a very old school way of thinking and thankfully most people in the current young generation do not have that feeling. If you are worried about what your parents will say, just let them know that there is nothing wrong with you, you just want to work through a few things. And you can quote them some statistics to help support you wanting to do it. Tell them that 85% of young people have gone to a therapist at one point or another. (By the way, I just completely made up that statistic, but the good thing about it is that your parents won't check on the veracity of it since therapy is a taboo subject to them. )
And I agree that the girl you mentioned is not at a point to be considering for anything romantic. She probably just sees you as a sensitive guy who is her friend. You are "harmless" to her and she probably hasn't even thought about dating you.
If she does decide she wants to go out with you, she will tell you and will probably break up with her boyfriend. Let these decisions be hers though, if they ever are. Just be her friend and be happy that you have such a great friend. She may even wind up setting you up on dates with some of her friends or giving you dating advice, etc.
Good luck.
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