I had a major breakdown unlike any in the past years

hello, back to the forum again, this is a vent post but tips and advice are most welcome.
i've had some trouble with depression and anxiety about a decade back, still following me to some extent for there are certain problems i still don't know how to adress, i'm 23 now, i've never had a great mood, always felt grumpy, sad, somewhat hopeless, low self esteem, i played video games most of the time i was home.
i have troubles with self esteem and patience, self discipline.
I never had any kind of relationship, never had sex, never had a girlfriend, at 23.
studying is hard for me and so is most of the ''boring'' and slow activities like reading.
but through the years although i wasn't great, i have managed to somehow keep my sanity for the most of the time and am having a normal life, i have a job, i do chores, i drive and so on...
but this month and the previous, march, had some of the most difficult days of my life, i have a problem with negetivity and over-thinking into big grumpiness.
somewhat started to get sick of my job, didn't feel so good.
However, at the same time period i got to know a girl from work, i thought she was really into me but i kept saying to myself that i don't want to get hurt all over again like past, unpleasant experiances with women, she kept texting me after work hours, having conversations, i tried not to go along with it, because i know it would get attached to her, so it kept on for a few weeks, and she got more and more ambitious, starting to give me teases and lines even at work that makes it hard to think she wasn't into me.
Constantly seeks my attentions, keeps saying that i'm not giving her enough attention, that i'm too cold towards her, keeps mentioning to me that if i'm noticing she keeps texting me AFTER work hours?
An actually attractive and smart female throwing herself at me? something off...
I've been trying continuesly not to follow it and play this game.
It even got to a level that im just sitting in my office, just drawing something for fun, she comes to the office, looks at my work, and she says that it's a nice drawing, but it would look even better if i dedicated it for her and put it in her office...
eventually i decided i'm trying to open up and try to change my life-long, self-destructive habits, and that i'm going to start with girls.
At this point, i was already very sure that she's really into me and just waiting for me to make a move...
So couple days back, we started texting for quite a long time, maybe an hour.
At some point she wrote: ''please don't tell me that you actually think that what's going on between us is something romantic, right?''
You know the feeling that when your body enters the fight or flight mode? and you start seeing black in your eyes, and kind of shocked? that's what i felt.
She says that she's sorry that i thought she's into me, and that she's nice to everyone, and that she thought we were just ''fooling around, like work buddies.''
I still had a hard time believing that, but what other choice did i had?
I got my heart toyed with, and i got into a very, very depressive and painful week.
I felt so bad for myself and felt humiliated and toyed with, still not understanding what has caused her to act like this.
I've been very closed and unloving to my brother and mother, for more than a decade, not showing any feeling to them, this time period and especially this specific even made me feel so bad, so sad, i just had to tell it to them and started crying, crying so much, i cried about 4 times that evening.
I had a breakdown, i've been very sensitive for a long time, i see it as my wake up call, and i have full trust in my ability to get out of the pit i got myself into.
Thanks for reading if you made it this far, i could never actually read the ladies well, i would love some insights about what you think about the things i've just said.