I had feelings for this one girl who I had a summer course with 10 months ago. She sat next to me and we got along really well with each other. At the time, I did not have any feelings for her.

Fast forward 9 months later and I start talking to her regularly again and occasionally text her. I try calling her to make plans, but it goes to her voicemail so I just ask her to call me back.

But then after a few days, I did not get a response. She also stopped responding to my texts and unfriended me on social media without any context.

My question is, what should I try/try to avoid next time so that I'm not left in the dust again?