I think I had a panic attack yesterday and now I feel dizzy

I guess I should start a couple weeks ago. I'm in my first year of my phd progam and I plan to study operator algebras. I probably could have taken my algebra and analysis quals coming in, but a week before they were meant to happen I panicked and so I'm in all first year classes; largely review material for me but very work-intensive so I don't mind.

About three weeks ago, near the beginning of October, I fell into a depressive episode and stopped doing my homework, stopped doing my grading, only barely showing up to classes. This was exacerbated by the fact that I have undiagnosed ADHD, and ran out of adderall and was unable to focus. About a week ago I got some adderall, started catching up on my backlog of work, started feeling a lot better about myself, etc. just in time for an analysis midterm.

During the midterm, I finished the first two questions in about 15 minutes. Then I stopped being able to think clearly, and started to feel a bit dizzy. I asked if I could step outside for a bit, was told that I could. I could barely walk in a straight line. Then I started hyperventilating curled up on the floor outside and my professor was super nice and is letting me retake the test another time.

Today, I feel like shit. I'm skipping my classes. I can't get out of bed. I have a headache. I know that if I try to stand up, I'll probably be so light-headed that I can't walk. I'm either in a new depressive episode, or the one that ended a week ago never actually ended. I have some cold symptoms too.

Even as an undergrad, I was never like this. I still had depressive episodes, but they were a lot more manageable. And I didn't have these things that I think are panic attacks, at least nowhere near this frequency of twice in the past 3 months.

Did I have a panic attack? Is this normal? Is it normal to be this dizzy/lightheaded almost 24 hours afterwards?