Hyperfixation based arguments are ruining my relationship

Hi so to paint the picture, me (19M) and my gf of 3 years (18F) have always had an extremely close emotional bond. We have a lot of love for each other and an overall healthy relationship . Our friends and family on both sides are supportive as a result .

But theres always been issues linked to my autism that have created tension in our relationship. Empathy, me not knowing how to deal with overstimulation etc . We have worked on these together and its what led me to actually getting a diagnosis in the first place. And these issues I found real solutions and coping methods for and we are all good with them now!

However, recently we have finally addressed an issue that was always there but she kind of hit her boiling point last night with it where she proposed breaking up .

I seemingly latch onto things shes said in the past that arent very noteworthy or very problematic at all and perpetually loop them in my head for literally weeks and overthink them to the point that im convinced its a real issue ,before i finally mention them .

Then, when I come out with them I just endlessly argue about them for no apparent reason , its like im arguing for no reason at all other than arguing ??? There is no real solution to the things I choose to argue about , and they tend to be things to do with our future, which i feel is because those things are more abstract so much easier for my mind to run away with . I get the overstimulation feeling when I think about those future things.

Despite not being a confrontational type myself which is even more confusing .

This happens monthly but my gf is just so exhausted with it in her own words its ruining her image of me .

I do have a theory on what I am doing here .

My theory is based on those conversations about vague topics about the future etc and automatically my autistic brain wanting to know everything about the scenario when it cant , latches onto the details that ARE there albeit totally insignificant in actuality and I construct my own detailed yet assumption based conclusion on what was meant by that conversation . And for whatever reason I get really upset although the topics aren't things I acrually care about .

Like I said im just arguing for arguing seemingly but im sure theres more to it ,

i think its my extremely irrational way of trying to find details in a space that there isn't many by nature and its just distressing me to such a point. And also her by proximity sadly.

I told her im going to seek some counseling from my diagnosis providers, but in the meantime hope somebody can tell me whats going on.

Any word is appreciated! Whether you guys have similar experiences or any advice. :) thanks!!!