help my gf (?) likes my best friend

Reality check here: she's not your girlfriend and there was nothing that you broke up from because you 2 were never in a relationship. You had one date a year ago.
I don't consider there's been anything underhand here; 2 single people have got together and it just so happens that you are friends with both of them. She's had plenty of time to get to know you and doesn't see you as relationship material, whereas you seem to be fixated by her and have built things up to far more than is actually happening; it doesnt bode well when someone is talking about 'space and boundaries' as it sounds as though you have crossed a line somewhere. It doesn't help that you sound insecure. Don't go interfering in the choice they are making.

we are (?) or were together, she admitted to being my gf and i was her bf. i introduced her to my parents as my gf, and her brother knows me as her bf. thing is we were/are (?) official, we were dating. we kissed, hanged out with each other. im not being COMPLETELY delusional here, she wanted to be with me at that time. after i asked her out on a date and we went a few more and became a couple, otherwise i wouldnt have been so confused? but we didnt break up. the talk about boundaries wasn’t a break up, she didn’t exactly say “im breaking up with you”, we acted the same way tho she got a bit more annoyed when i was being too clingy. but we were still together, she still told people we were together and she still liked me. and then she likes my best friend all of a sudden and when i found out, she tried to comfort me, in a weird way, but yeah! she said she still liked me, but she needed to figure it out and pick which one she wanted to be with, so now im assuming we arent together anymore. i dont know when we officially broke up, because shes the first girl ive been with and im not 100% sure but kind of thought you had to tell the person that your dating that you dont want to be together.

If you reread your first post you'll see why I was confused by it: 'this girl', one date a year ago, likes your best friend, nothing that sounded like an established relationship.
It's not good that you are considered clingy - which comes over as what I described as fixated - and the pair of you don't have the communication skills to discuss this properly. So sit her down and ask her what is happening; if she is truly thinking about someone else, ask why. If there is nothing that can be fixed on either side, move on from her. She's already emotionally cheating and manipulating you by staying with you while she weighs up her options and that is not someone who is 'amazing'.

yeah, sorry ab that, i just dk if she is my gf anymore? so i wasnt tooo sure how to phrase it
thanks for ur advice tho, ill do that later today when she comes back!

"the talk about boundaries wasn’t a break up" ah.... it's pretty much 99% a breakup, that's the sort of thing people say when they don't want to be in the relationship any more. Again them thinking you're clingy is much the same.
What sort of experience does she have, is this her first too? As it sounds like neither of you really know what you're doing or what the other wants. We've all had to start out somewhere like this and make mistakes, as you say it would be nice if everyone just communicated what they wanted clearly. When you're younger or less experienced it can be quite common to get into a relationship pretty much for the sake of it without giving much real thought to how compatible you really are so they're often doomed one way or another after the initial honeymoon phase.

what happened then"??

well we broke up. more officially that time, i didn’t see her for a while. me and my best friend sort of stopped being friends as well, but then something came up so we all got together. me and my friend spoke and apologised to each other. i did speak to her afterwards, but she was very adamant in not really knowing what she wanted and that there were parts of me that she liked and parts she didn’t like. it became clear that the reason she liked my friend was because he wasn’t me. (he didnt have the relationship history i had with her, if that makes sense)!! then she sort of stopped speaking to me about it and it was awkward for sometimes.
something came up, where it was just me and her and we spoke again about ‘us’, and she was more open this time. she told me that she was struggling with her identity and feeling insignificant (in some ways). i was too overbearing in our relationship, and she expressed that she didn’t like that more clearly. she said she still likes me and that she knows we’ll be together but that she needed some time to herself. (sorta just wished i knew that sooner!) anyways, we got back together only a week ago or so! we’re giving it a new shot, and it’s going pretty well! i feel like i understand her a lot more than before and that we can rely on each other for support! just hoping it stays like that!

aww im glad it worked out!!! gl!!!