Quick follow up:
blurry vision (intermittent)
head feels swollen or "puffy" mostly near eyes
foggy brain/difficulty being present/focus
dark thoughts/impending doom
weak/frail (like if I had the flu)
Welcome to the crowd who have had their lives made worse by cortico-steroids. If you went onto a site devoted to this instead of here you'd see that what you're going through is more severe than most but not, unfortunately, unusual. I've been stressed about this for a long time because I have some bad injuries that probably require cortisone shots if I'm ever going to get back into the gym, but my psychiatrist has long counseled against it because of a bad chronic anxiety problem. I can take small amounts of this stuff, the small doses dentists sometimes give you for example, but even that keeps me from sleeping at all after a couple of days. I think the lingering effects are partly one of the main side effects of taking these drugs, which is joint pain and tissue damage, but most likely not from the small amount of the oral preparation you took -- this is more from repeated shots. But some people are extremely sensitive to this, and you're not the first who has come here with this problem. I think, though, that there is a second part of this, which is that when you do something that makes you feel like you felt when you had that severe panic attack took a budding but so-far minor anxiety problem and cemented it into a potentially chronic problem. Working out hard can make some people feel similar sensations to what they felt when they had the panic attack and the brain does its anxiety thing -- it's what happens in people prone to anxiety problems. It's what happens in PTSD sufferers -- most are found to have already had feelings in life that correlate with depression or anxiety problems that hadn't popped out yet but might have anyway. If this were me, and it isn't, I'd find a psychologist as quickly as possible who specializes in anxiety treatment and get to work fixing this before it becomes who you are. At this point I don't think medication is necessary -- but if it keeps getting worse and therapy doesn't help it might get there, but most people get over this kind of thing if they realize it exists early enough and work through it. I'm betting you're one of those people.