i talked behind my friend's back and she found out, what do i do?

[shay]

So i was chatting with my crush and we started talking about my friend. We went out the day before all 3 of us and he felt like she was bored and it was his fault. I said it's ok and that she is easily bored and other not so good stuff about her to make him feel better.Also i told him that we almost lost the movie tickets. Also that she felt like a 3rd wheel. Then my friend went on my account and read through the chat,she says she wanted to see something else, not the chat between me and him, but she saw it by accident. She saw her name there and read through it. Now she is pissed at me. She says we have been friends for so long and now u betray me for a guy u have known for a month ? He doesn't care for u. She said she doesn't want to talk to me anymore or see me. She said go out with him and why do u tell him stuff u know i don't want u to tell him. She is like - Why is he so important to u? I cant trust u anymore, i will never go out with u again.
So now she doesn't answer her phone or my messages. i feel like crap, i'm really guilty, she is so right, we have been fighting a lot lately with her, it is not the first time i talk about her tbh, i had no idea she will go on my account. she has the right to be angry i know. i know i'm a bad friend. i bought her gifts but she doesn't want to see me so she probably won't accept them.how can i make her forgive me. ( i know its hard to forgive such a thing) but i cant just forget her and move on she is very important to me and we have been friends for ages. What do i do ? please help!