I have been finding a good friend of mine (she's in my circle of girlfriends) more and more insufferable over the course of the last year / year and a half and have been pushing her more and more away. I don't want to stigmatize mental health and I know you cannot really diagnose people as a non professional but I am trying to understand to also to have a better idea of her and the situation in general.   
She has always had a very egocentric personality (and all of the other girlfriends are aware of this) but I used to be able to live with that. She does suffer from depression and anxiety (which I do too btw). 

So I have been away from the city we live in due to family reasons for most of 2021 and you know, covid etc., we had not been seeing each other, just some talks on the phone from time to time. 

When I was back and met up with her again I had been coming from a year of grief and basically ptsd and have been trying to talk about my problems but all I could hear was her talking about her sex dates and in a very aggressive way about her promiscuous situations, which I could care less about tbh in that moment. We were outside taking a walk and she was talking very loud about details. We were sitting close to an older man and this was making me super uncomfortable and when I addressed it so she could tone it down she was like "who the hell cares". That point was when I realized we are in very different situations of our lives and this is not a person whose company is good for me atm. 

Unluckily we had already planned a getaway weekend with a third friend of ours. I had a really bad feeling and did not want to go but I could not cancel it short term. During those 72hours it was like she was on a show and we were her audience. She has been talking non-stop during driving and also when we were supposed to relax at the airbnb we were staying in. I was not really feeling well in general but mostly due to her behaviour and was being very passive and just letting her talk. The third friend also barely could intervene in her "speeches" but was giving it more effort than me and she didn't mind (we talked a lot after the whole trip with this 3rd friend and she confirmed to me that it is not me but that she can handle her better because she has kids lol and that she's not in a vulnerable phase of her life like me atm). The thing that left me speechless is that she was talking SO FAST, her speech was accelerated and she went from topic to topic always too in depth, TOO long, as if she was holding a TEDxtalk, but in order not to let us talk (at some point I honestly could not care less) sometimes she accelerated the speech to finish her sentences. And of course she was talking about herself as if she was some kind of heroin in a novel. Stuff that I've heard 1000 times already and she was repeating it and going into detail as if they were the most exciting stories in the world (for example, her allergies as a kid; her style of driving and how she learned; she is a smart woman and some topic ARE interesting but the way she monopolizes the conversation just makes you wanna roll your eyes and slowly pull back). At night I would go to bed early because I was so over it and tired and they were staying up late drinking and smoking (we are 30+ women) and in the morning she'd be the first one to get up fully energetic, already starting with her speeches when I just really wanted to drink my coffee in peace and enjoy the nature and silence. I've known her for many years and we did someholidays together already and honestly this was a new person to me. It was like her having her flaws exacerbated thrice and I was just bewildered.  
On the drive back it was as if my batteries were empty, I was sad and anxious, mostly because I realized this person is not who I thought she was and I basically now would have to come to term with the fact that I lost somebody who I used to think was a good friend. In my mind it was clear that for my own wellbeing I HAVE to distance myself from this person. Which I did. After this trip I came to know she put herself in many sexually dangerous situations and was basically acting like a nymphomaniac. 

Do you all think this might have been hypomania? As far as I know now she's acting more laid back now and has been suffering from depression and anxiety again...