I recently met this girl she is 3 years younger than me. (I'm 21.) We met off a dating app she said I was the first one she liked on there. The next night we hung out and she said she said she never had these feelings for someone so fast. I knew I liked her but I didn't get butterflies the way she said she did. We were together for the most part the next day. It's been several days since I saw her. I feel like I can't stop thinking about her and it's starting to get to the point where I'm obsessing over it and the fact she takes awhile to respond to me. Like for instance we had planned to hang out today but her friend came over last minute and she is taking awhile to respond on her phone and I can't stop thinking and feeling upset by it. I feel upset because I don't know if we are going to be together and I was really looking forward to it. I also felt insecure when she took awhile to respond a couple days back when her phone died thinking I'm not good enough or maybe she changed her feelings about me.
And that's the main reason I'm posting this how do I stop letting this take so much effect on me? I want to feel okay if possibly things weren't going to work out and to be happy with being alone with myself. This would be the first real relationship I'd be in. I feel not that it was rushed but that it is unreal. I don't know for some reason it doesn't feel real but I know I'd be torn apart if she leaves.