How do I make my boyfriend (19M) understand me (18F)?

[Please do note that english is not my primary language, thank you!]

Hi! F18 here. Boyfriend, 19M, and I have been together since after eighth grade (five years now). We are currently in college anda are taking different courses. People around me have noticed something and told me that I took "your partner is your best friend" too seriously. I don't go out if it's not him I'm with, or do anything in general if it's not with my boyfriend. I'm not saying that it's bad because I am a pretty introverted person overall, but it's gotten to a point where I basically would not be able to function if we don't talk.

Here's the thing, he likes to ignore me during our fights. It's important for me to note that we live two hours away from each other, and social media is the only way we can communicate unless we're at school (but I am transferring to another university soon, so this will be a problem as well). However, he KNOWS I have really bad PTSD from being ignored as a child by my family (yes, family.) as a means of punishment. The kind where they would seriously act like you're not there and even talk about you even though you're right there in front of them kind of punishment. I haven't gotten had any help for it yet but I am working on it.

Now my problem is that whenever someone shows me even a slight hint of them about to ignore me, I just go into this downward spiral of anxiety and panic. He wasn't like this before when classes weren't done face to face yet during the pandemic and I have also sent him lengthy messages asking him to stop ignoring me or giving me the cold shoulder whenever we fight. At this point, I kind of feel like he does it just so I would stop talking about how I was feeling at the time or when I am confronting him. He sometimes just tells me that I'm too negative about things and that I should stop overreacting to things. He only stops and talks properly when I start begging him to and gives me a half-assed apology all the time.

Please don't be mean about it. I don't have anyone to talk to in real life that would understand and I am also not in contact with my family for obvious reasons... I love this guy and I've pictured our life together and his family is no different either, they've loved me like their own as well. Thank you so much. :)

TLDR: Boyfriend ignores me despite knowing how I feel about it and continues on doing so until I beg him to stop.