Is it normal i'm sometimes uncomfortable around my bestfriend

I have this girl and she is my "bestfriend" we have been bestfriends since 8th grade. She has been there for me through all of my problems and happy moments. So she meets this girl and she is a lesbian. So my bestfriend and the girl start liking each other and start dating (no problem with me). Going into highschool me and my boyfriend (still dating but has been a year now), i start to notice my bestfriend flirting. The signs she was giving me made me feel like she likes me like rubbing my thighs, dancing on me, touching my butt, trying to kiss my cheek, calling me baby, following me every where i go (but not stalking) my "bestfriend" doesnt have many friends so she want to be with me 24/7. So me and my boyfriend was talking and he had noticed the same thing. I have no problems with lesbians/gay. but now i feel so weird around my bestfriend when we are alone. I love my boyfriend but i dont want to loose my bestfriend because i dont like her back..