Princess Twilight how do you feel about fillies that like fillies? I'm scared to be myself because of what others might think.
I don’t see the problem. My best friends are fillies (well, strictly speaking they are mares like me, but in a colloquial sense they are fillies) and I like them very much. Surely, that’s pretty common. If it’s not where you are, well, as the Princess of Friendship I would argue that who you care for is a matter of their character and how they treat you, and it’s not up to other ponies to decide.
I suppose sometimes ponies might not approve of your choice of friends, but you should ask yourself whose opinion you value more: theirs, or that of your friends. Assuming you value you friends’ opinions more you shouldn’t abandon them because others might disapprove.
Oh, and trying not to be yourself rarely works out. You really should embrace who you are. Well, unless who you are consists of enslaving all of Equestria or something like that, but clearly that’s not the issue here.