It's dangerous to be in love with a friend. It's even more dangerous when you know you depend on them for love, support, and guidance, even outside a romantic relationship. When you fall in love with them...you must navigate carefully. Being in love with someone you already trust can come with a great, freeing feeling- if they feel the same way. If they don't, it's a simple crushing oppression, and that makes you less likely to see them, talk to them, etc. You probably won't lose their friendship, but because of your growing fondness, you could grow apart in time.
A few tips for surviving having a crush on your friend:
1. Wait it out. Sometimes, these things take a bit of time to be worked out of your system. Maybe you haven't had a romantic interest in a while and you're just bored. Take some time and really think about how you feel.
Exercise: Write in a journal every day for a week about what you're thinking, and how you're feeling. It doesn't even have to be about the person you're interested in; whatever comes to mind is what you should write about. Let your thoughts guide you.
2. Separate yourself from them for a time.
Exercise: Don't go out of your way to not talk to them, but don't go out of your way to talk to them, either. Just be neutral.
3. Talk to them. They're already your friend; chances are, they trust you. And if they trust you, you should trust them. Remember: because they're your friend, you know they like you already, at least a little bit.
Exercise: Practice what you're going to say in front of a mirror, or write it down. It probably won't come out like how you've planned, but you'll feel better with the practice, and you will be able to figure out what are the most important points you want to make.
4. Acknowledge the fact that you may never engage in a romantic relationship with them, but you can still have a friendship.
Exercise: If they turn you down, give yourself time away from them. Talk to them about your feelings, and let them know that you may be able to have your great friendship back once you take some time for yourself. Don't return to their side until you know you've gotten over them. It's too easy to get sucked back in.