Agoraphobia & Social Anxiety Support Group
Agoraphobia is an anxiety disorder, often precipitated by the fear of having a panic attack in a setting from which there is no easy means of escape. As a result, sufferers of agoraphobia may avoid public and/or unfamiliar places. In severe cases, the sufferer may become confined to their home, experiencing difficulty traveling from this "safe place."

Do you have a therapist, psychiatrist, etc?
I have agoraphobia too, and medication and therapy have helped me. I would suggest trying to seek help. The sooner you do it, the quicker you could get over it. It is harder to try to deal with this without professional help.
I'm so sorry to hear things are rough right now. I hear how much you are struggling, and can only imagine how difficult it has been to meet the demands of college under these circumstances.
I am wondering what it might be like to tell someone (a professor, your advisor, etc) at school about what is going on. Can you think of anyone you might feel comfortable talking about this with?
It can be so intimidating and scary to open up to someone like that, and I think it's important that you find the right person/someone with whom you feel comfortable/who you think would understand, so it feels a little less scary. They might be able to help you access resources on your campus that could help. And you might be pleasantly surprised at the support and understanding you receive.
I am pretty sure all campuses have some sort of Office of Accessibility/Disability... it might be worthwhile to find this office at your school/give them a call. They might be able to help set up some accommodations so that you are better able to succeed in school during the tougher times. By law, schools must accommodate those with documented illnesses (whether they be physical or psychological) and nobody can discriminate against you for it. Even if you never need to have any adjustments made regarding your coursework, it's good just to have the possibility there if you should need it.
I would also encourage you (if you haven't already) to look into your school's psychological services. I am fairly certain all schools offer therapy services free to students and also usually have a ton of referrals for other providers in the area.
Please know you are not alone. So many college students (myself included) struggle with very similar things, even if it is not always visible or apparent. It sounds like you have worked incredibly hard to get to where you are at in your education, and that you have an amazing future ahead of you. Keep going and know that the hard times will not last forever.
Please keep us updated if you'd like (I'd love to hear how you're doing) and let us know how we might be able to help. Hang in there.