I have some concerns for my friend.
She's 22, thinks she maybe bi sexual. All her life she has gone out with guys and thought guys were extremely attractive. She has had random sexual thoughts of females but never to the point where she thought she would be a lesbian or that she would go through with any of these thoughts. But not she thinks she might be bi.. She's a huge worrier and worries about everything, and has worried her self to the point where she thinks she maybe losing interest in guys when clearly a week ago she was wanting a guy at the bar. She is always worrying and thinks she has something when she really doesn't like aka. A sickness or she thought she was pregnant over 5 times believe she had symptoms of it. Anywyas is it normal for her to have these random sexual thoughts of females at her age and does this mean she is bi or gay or is she just crazy.

help.

My opinion: Bisexuality is not something that someone can wonder "if" they are. It is a choice. She may have temptations, but everyone has temptations for things that are not "typical"... or whatever other word the person calls "normal".

Even if she acts on a temptation, that does not make her bi-sexual.

Only if she decides she likes the lifestyle of sexual activity with a man OR a woman, and acts on that decision, then she is indeed bi-sexual.

And can she lose interest in guys overnight or is this all in her mind?

I believe that is more a relationship issue. I'll move this there so it can get more attention.

She may need professional help.

It sounds like she's desperate for attention far more than a guy or girl. I would back off and tell her that since your straight you can't help her.