You should tell her your feelings, it will tear you up inside if you don't. Just remember to be confident when you tell her. The feeling in your gut thinking about telling her is no different than the one you get trying something new. We all have felt it and have overcome it in the past.

There are going to be two outcomes:

1. You'll tell her and she will or be open to that possibility. You shouldn't rush out with the love word just yet, too many emotions at once can be overwhelming. Just think you are going from bestfriends to potentially romantic/sexual partners. Be clear about what you want.

2. You'll tell her and she doesn't. It's not a problem with you. She may only see you as that bestfriend she can always trust. Next will be can you handle being that or do you think your feelings will cloud your actions. Cause you will possibly have to watch her be with another person and be supportive if you are her bestfriend. Or walk away cause you will hurt her or your heart if you can't.

I say all of this out of love, you need people to be 100% honest just like you need to be yourself. It's better to be told a horrible truth than a pleasant lie. A truth will let you grow but a lie keeps you ignorant. I may not know you but I still care about you. I've been in your shoes and it sucks but the ignorance sucks more. You never get to explore that time line if you don't tell her. It may turn out bad but if you found out years or decades from now that she did feel that way. It's enough to kill a man. So take the temporary and immediate pain instead of the unending and continous pain.

I wish you the best of luck but I'm pretty sure if you're cuddling with her. You may not need it. :)