Am i completely screwed?

So i just got out of a long relationship so i was checking this girl out and a friend of mine had one of her friends get me her number, so i texted her and i didn't want to be in a relationship so my sister told me to tell her i just wanted to sleep with her or even just be friends with benefits, but now she wont talk to me at all. What should i do now? Am i completely screwed? Sn(Side Note) When i see the girl she just gives me a dirty look like shes creeped out and she laughs to her friends. I feel so uncomfortable around her.