I have romantic feelings for my best friend
How do you feel about that?
I can't stop thinking about her. I'm both confused and excited.
I think that you should tell her. She should know if your feelings are truely that deep for her.
I can't. I would feel like a piece of shit if she rejects me.
You need to no bottle up these feelings. It is unhealthy, plus you will never know how she feels about you if you hold back. You should avoid falling into that pit of regret.