I was out with my elder sister's friend. She is extremely

I was out with my elder sister's friend. She is extremely beautiful and has big cleavage. I have been knowing her since my childhood and I have never looked at her that way. When we were out ahe was standing behind me and accidently my elbow hit her breast. I was embarrased and gave a stupid smile. She had caught me glancing at her cleavage once before. The next year when she called me to wish Happy Brithday I was frustrated and didn't thank her in a proper manner. This made her angry and she stopped talking to me. I tried to text her a lot but she didn't reply. She started talking after some time but she still hates me and even I hate my self!!! What can I do? I'm stupid.