Guilt for being easily overstimulated

I'm currently in a foreign country studying the language with the intention to work here after my program is over. However, I have needed to ask for more accommodations than I ever have before. For context, in high school I was a straight A student with little effort, and in university I graduated with honors (with much more effort than high school). I did not use accommodations back then for either institution, although I struggled with depression, anxiety, panic attacks, and a hormone disorder (as well as a couple other problems that I am still in the process of getting diagnosed/identified). I found out this summer that my panic attacks were not random like I previously thought, they happened when I was overstimulated and unable to keep up with masking. I think the fear of being unable to present myself as a confident and functional person was what drove that anxiety. These panic attacks are what actually drove me to pursue a diagnosis for Autism, which I received this year.

I understand logically that having autism and the subsequent needs is not a bad thing. It's also not my fault or choice to have them. However, my hormone disorder has gotten worse (I went from a competitive powerlifter in high school to barely being able to walk to the grocery store (10 minutes of walking) without being exhausted). I also seem to have developed other physical problems that impact my cognitive ability. There are times that I cannot comprehend language, in written and spoken forms, including being able to communicate myself. Basically, I'm in a constant state of being on the edge of overstimulation because of pain and fatigue, which is making my daily life so damn hard. Learning and living in a foreign language is stimulating, and it's a huge city where advertisements are loud and bright, and the overlapping sound of people talking, walking, and existing has driven me to hide in elevators more than once. And then when I go into shutdown mode or have a meltdown I tend to transition into a period of dissociation, where everything feels so unreal and I start to become delusional and paranoid. I know this isn't an underlying unrelated issue because it happens in specific patterns: overstimulation -> shutdown/meltdown -> dissociation -> recovery.

The point of this entire explanation is that I have had to ask for numerous accommodations in my program (which is prestigious and competitive to get into) and have not been able to be a good student. At least, I am not able to be the student I want to be. The program is intensive and I cannot keep up with the structure they have. So, I have had to ask to make my own structure (which works so much better for me and I am retaining and learning so much more than I was when following the original structure). I have been feeling very anxious and guilty for getting into the program and being such a needy student. I feel like I somehow deceived the selection committee (even though I was diagnosed months after being accepted). The teachers are very supportive and the director has been overwhelmingly helpful, but I can't help but feel like a burden, or feel guilty when my brain goes blank in class because I'm shutting down. (The director has an autistic adult son so he has been very understanding). The anxiety and guilt are just making everything worse. 

Basically, I can't keep up to my own standards, and what I perceive to be the standards of others. It's also driving my fear of being able to succeed as a working adult (I'm only 23, so I understand that this is a fear that stems from a lack of life experience). I think that my stimulation limit has not changed, instead I think my environment has become increasingly more stimulating as I progress through life. Is it possible to increase my stimulation limit? Also, how can I manage my guilt and anxiety from being unable to perform at the rate of my non-autistic classmates?