Friend problems?(Include details)?

I can understand where your friend Alexis is coming from. If you put yourself in her shoes, she may feel left out, or that you're "stealing" her best bud. But at the same time, you have no intention to make her feel this way. So tell her that. Even though they're your friends, i think it's a good idea to distance yourself slightly. not toooo much, but let them be together so that Alexis feels that it isn't a big deal. It's also her problem, so she should talk to Eliza on her own and tell her how she feels. Give it time, Alexis probably isn't used to having a new friend around. plus she's the one who introduced you to her best bud so it sucks if you run off with her instead of Alexis (which i doubt you are!). I hope that made sense! good luck, and don't worry too much, things will turn out soon!