Have I lost my best friend?

So I've messed up a bit.

I've had a female friend for about 10 years now. We're both part of the same friendship group and have always been fairly close. We both went off travelling and to College/Unis away from the group while the others stayed in our home city but whenever we both got back we'd always pair off and talk about everything from relationships to anything really. It's always been nice having our little friendship and she admitted once the main reason she came back was to check in with me instead of others in the group (not that she didn't get on with anyone, she was just closer to me).

Well last year we started sleeping together randomly. We didn't plan it but we ended up dating for a few months. Early this year, we realised it wasn't really working. Everything was great but we found ourselves just arguing over silly stuff. We said we'd stay friends and to my surprise she actually meant it. The weird thing was that we were now closer than we ever were before we dated. We carried on hanging out every few days and talked over the phone or message every day which was great. We started to refer to each other as best friends and I actually really got used to having someone I could turn to no matter what. Obviously I'm close with my other friends and I see them all the time too, but this was a different kind of friendship.

The problem is that we still had sex occasionally. It wasn't planned but we did find ourselves chilling at my place and we'd just fall into it. We knew there was obviously some feelings involved but knew it wasn't gonna lead to anything. Our other friends were confused but we insisted we weren't dating which we weren't. Eventually we agreed to stop the sex because I think she was starting to feel confused. I did ask if it was because she still liked me and she assured me it wasn't.

Well about two months back, she broke her leg and said she wouldn't be able to make it to mine as much which was fine but all of a sudden when I would try to plan things I was getting nothing but excuses. I've offered to come see her but she kept saying she was all of a sudden busy with her other friends who I've never heard her once mention. I understood but it started to become more and more frequent. I started to get really short replies or no replies for hours.
She even started to pass on pre made plans without much warning which started to rub me the wrong way. We were due to go on a trip which she bailed on at the last moment and even decided she wasn't gonna come to my birthday meal she planned for me. She turned up to my birthday party late and couldn't understand why I was a bit hurt. I explained that I was confused why she's creating distance but she kept refusing to admit she was.

This carried on until last week. She randomly apologised about not being a good friend and we talked it out. She then cancelled on me two times in a row but I carried on being supportive because she said she was having a really hard time lately.
Suddenly she told me she's met someone and basically she's cancelling plans with me so she can be with him. I got annoyed because I'm suddenly being dropped. I understand that she's in the beginning of a potential new relationship but that's no reason to just throw me out. I've had to cancel plans we had over Christmas because of this and I know I may be overreacting but it feels **** to find out all your time hanging out with someone was literally out of convenience and because they had nothing else to do or at least that's how it feels to me. I've literally bent over backwards all year helping her out with stuff and even called in sick to work to comfort her when she was feeling down because she's my best friend. I told her I was annoyed and we didn't speak for a few days.

I went out on the weekend for a friend's birthday and she was there. We didn't really speak until later in the night when a friend misquoted something I said and she started an argument which was embarrassing as it was in front of everyone.
I went home but she ended up letting herself in in the early hours and we talked when she realised she made a mistake. Eventually drunk me being an idiot offered the ultimatum of me or him. I didn't mean it but I did say it which was stupid. We argued and it ended on weird terms when she drunkenly kissed me and she left.

The next day we talked and apologised about everything but later in the day she explained that her new guy isn't happy about her coming to my house and she can't speak to me for a while. I contacted her the next day and she said she really wants to be friends but it's not healthy to be arguing all the time and making a mess. I asked if we could meet to perhaps talk sometime soon and she said she'll let me know.

Against my better judgement I messaged her yesterday just to say hi. I was missing her and just wanted to talk. She didn't reply until this morning and again this evening.

Have I lost my best friend?