<human>: Condense the text into a few key points

A little backstory: I was a relatively fat kid not too long ago (17 M). I worked out, ate right, and lost about 40 pounds. This made me feel awesome and helped my confidence skyrocket (I never had a girlfriend before/kiss). 

About 10 pounds into my weight loss I asked this girl, lets call her Grace, out who I had a massive crush on. Im talking borderline obsession. 

She rejected me and we didn't talk for a few months until school started up again. She saw my new look and personality and instantly started flirting/texting me again. I didn't really want any part of it, even though I still had feelings for her. 

Fast forward a few weeks.

I met this girl, lets call her Sarah, who is seriously amazing, I mean, I cant imagine a better fit for myself. Sarah and I have gotten quite close over the last few weeks or so, and I was planning on asking her out. Of course, as I was talking to Sarah about this dance we were going to, Grace texts me saying that she messed up when she didn't say yes to me months earlier. 

I of course freak out, ask Sarah for her advice, she says go for it, I do, and now I have a date. 

Yaaay, a lonely teenager may finally have a relationship. But, now I am all confused because I had these developing feelings for Sarah, and now I'm about to go on a date with Grace. 

When I told Sarah about Grace and me, she said congratulations and stopped texting me relatively soon after that. I don't know if I've hurt her or if I've made her jealous.

Im a little confused at the moment. If you have any support or help it would be greatly appreciated.
<bot>: Hot girl rejects me, I get skinny and get a new [f]riend, hot girl wants me back, I say yes, am confused/did I fuck up?