I like a girl. I dont think she likes me the same way I like her. She's currently single, but I'm scared someone will take her away. I'm scared of this happening to me:

Never seek to tell thy love,
Love that never told can be;
For the gentle wind doth move
Silently, invisibly.

I told my love, I told my love,
I told her all my heart,
Trembling, cold, in ghastly fears.
Ah! She did depart!

Soon after she was gone from me,
A traveler came by,
Silently, invisibly:
He took her with a sigh.

This poem embodies what I'm scared of. I'm scared that if I tell her she'll flat out reject me or tell me she always thought of me as a brother. And then she'll fall for someone stronger, prettier, or richer than me. It scares me so much anon that its beginning to eat me from the inside. Every time I think about her all I think are of scenarios are in which she ultimately rejects me. Why the fuck am I like this?