I'm in love with my best friend?

Me(I'm a female btw) and my best friend have been friends for 3 years now. I'm exactly a day older than her. She's addicted to drugs and drinks all the time. I hate the way she acts and I hate when she constantly wants to get high with me. She frustrates me to no end. I feel like I'm babysitting her when I'm around her. She wants me to smoke (weed) with her all the time and then she gets weird when she's high. Like she likes to wrestle with me (she's quite stronger than me and much taller than me too, im really short)then she'll pin me down to the floor and straddle me and just do weird things like pretend she's riding me, like I'm a guy or something. She'll grab my boobs and kiss my neck, it makes me so uncomfortable but at the same time I like it? Then we sleep in the same bed when we spent the night at each other's house and she likes to cuddle with me, which I like it too honestly. When we're laying there sometimes she'll breathe down my neck and try to tickle my sides. It's weird because I honestly do not think she's a lesbian or bi-sexual, she just likes playing around. I guess I've developed feelings for her in some odd way. I think this maybe me why she pisses me off all the time, because maybe I want the best for her? I myself am not a lesbian, although I might be bi-curious, I don't know. I can't ever imagine being in a relationship with a woman, but I am attracted to them sexually? Anyways I'm straying off topic. There are just a lot of mixed feelings everywhere. She doesn't even know I feel this way about her. I love her so much, as a sister. But then I have these weird feelings towards her. UGH. When we hang out I have so much anxiety built up around her, like I feel as if I say or do the wrong thing, she'll hate me or be mean to me. Is this normal?