Do you question this because you think she may have feelings for you and you worry about giving the wrong impression?
Any friendship needs chemistry to survive so if there is "nothin" than what is the basis of the friendship? It can be trickier to have a functional friendship with the opposite gender, especially if one or both of you is single, but some of my most fulfilling friendships are with males and I can't imagine limiting my social circle to just girlfriends.
Thor Galore I think my cohort here got this right. Yes you can be just friends with a girl, but you're probably attracted to her too. That doesnt mean that you cant sustain a long lasting and fulfilling platonic relationship.
Also, when you jerk it and think about her she wont know. Unless you tell her or send her dick pics. So dont do that.
So it's sheets once a week. What about blankets/comforters?
This is something I struggle with. RE blankets, I like to wash the ones that are out in my apartment once a month or so. RE comforters, I have a duvet cover which allows for more regular washings than a full comforter does. I also tend to do once a month but I also sleep under sheets and not directly under the comforter no matter what.