Is it normal to get confused about sleepovers?

I have a good friend, we have sleepovers constantly (whenever we're in the same city coz we travel a lot) but something bothers me.

My friend (we're both girls) has night terrors so we sleep on the same room most of the time. Problem is she sleeps in the nude and likes me to spoon her or she spoons me as well.

I try not to have dirty thoughts however I end up very turned on and it makes me uncomfortable.
It seems she pretends it's all pure and natural but I feel she's teasing me.
We had sex before and it was great but I don't do casual sex anymore. I sense she's playing me.

Is it also my fault? Am I weird to sexualise our friendship that way?

Please help me with any comments.