I fell in love with the best friend of the girl that fell in love with me

This is my first ever reddit post, and I am starting of with a hard question of mine. It is really serious for me, because I am struggling really hard, so please, if you give advice, try to be serious. So as the title says, I fell in love with the best friend of the girl that fell in love with me.

First of all, side details. I am a 17 year old boy, who fell in love with a girl, who's 17, too. Her best friend is a 16 year old girl. The girl, I fell in love, and me already had some kind of relationship. 5 months ago I already had told her I catched feelings. She kind of related, but said it would take her some time to have an answer for this question. Her and I were best friends at that time and even though I waited for an answer, I was really happy. So, it went on with us, we were hanging out really often (like 3 times a week). As the time goes by, she still didn't have an answer for me. We even ended up going on a 3-days trip to a city together and there still was no sign of an answer coming up soon (We are 2 months in, since I told her). So I asked her what was going on, and asked if I would get my answer soon. She said that she couldn't tell. To cut this shorter here, I was waiting for more than 3 monts in the end, ending up telling her I am done with waiting, and that this situation we are in would not make any sense.

So, now to the main point. It's been more than 2 months ever since we "broke up" with the situation. Last week-end her best friend, meanwhile mine, too, told me she fell in love with me. We kissed. I was triggered, and couldn't handle the situation, ending up telling her that I think a relationship wouldn't make sense to be started, because I am not fully in love with her. See, I kind of really like her, but more likely as a friend (I don't feel attracted towards her). Couple days ago, there was party, where I met my old crush. We hang out a bit and had much fun. We actually came back to the "us" topic, and her completly dening the thought of starting a relationship with me, because of her best friend. She has some feelings, too, but doesn't want to think about a relationship, because of her friend.

So now, I am here, thinking about what to do. I know, I kissed her best friend, and that might have been wrong (actually had feelings for her, felt wrong in the end). But I can not get over this damn girl, we already had so many awesome moments with each other, I can't let go. So, if you think you could help, YES PLEASE DO IT. :)