Can you reach out to any former mentors or people at other universities you might have connected with? I also second considering reaching out to the Dean (I email ours directly and stuff sometimes happens). Maybe get involved in some University stuff outside of your department? Student government often has positions on committees they are trying to fill and that was a great way for me to find some support and mentorship outside the dept, which was really crucial for me when I went through the 5th year bs (not so much like yours, Im in STEM, so its less of a writing and need access to mentor issue and more of a why am I working on this research that has nothing to do with my thesis and also crappy teaching assignments) I also have depression and anxiety, and I know that just amplifies the already high level of crap I deal with. I'm sorry you are dealing with all of this, I hope you can find a little support somewhere. You have already accomplished a lot, try to regain/hold onto some confidence and let me know if you figure out how to get any enthusiasm back, I could really use some myself. Oh first year me was soooooo jazzed. Sigh.