Why did she hug me like that? Do you think she likes me?

Hey, well there's this girl who seems to like me (if she does she is extremely brave). She is pretty shy (like me) and doesn't have many friends (also like me). We hadn't spoken more then a few words to eachother before she randomly hugged me. Here's how it happned: I was walking to cl like I always do with one hand in my pocket and the other holding my books. I was lost in thought (people tell me I look sad when I space out like that). Suddenly someone wrapped their arms around me from behind while flying foward. I stumbled, but regained my balance. Whoever had their arms around me squeezed me tightly with their arms, snuggled their head against my neck, and let out a big sigh. after that they let go and I turned around. I saw a girl who I recognize from a group I'm in. I asked what that was for and she said "y-you uhh... You looked like you needed a hug." then ran off before I could say anything else. About a week later I decided to take a risk (remember, I, aswell as her, are really shy) and return the hug. I saw her at the little meet-up I had with the group we're in and tried to hug her, but got to nervous and decided to just talk to her. I tapped on her sholder and smiled. I said "Hi", but she looked at the ground and said she had to go check something for the group and ran off. Lastly, I finaly got the courage to hug her. When everyone in the group was going home I ran over and hugged her and quickly let go. I told her I was repaying her for making my day. She started blushing a bit and smiled. then we left. I think she might have just thought I needed a hug, or even looked like someone else from behind. I really doubt she likes me, I'm nobody special, and there are plenty of other guys who are better then I am. Now, it isn't as likely as it sounds. I'm not sure why she'd like me, I'm just your avrage, nerdy, inexperianced, shy guy. Don't just ume that she likes me because it sorta sounds like it. Take a minute and think about all of this. Please.