Who knows what the real cause is. Might be the steroids, might be the virus, or the lack of sleep, being in an unfamiliar environment, the stress of being unwell and scared. Most likely a combination of them all.
The important thing is you remind yourself that you will get better and it won't...
Get well soon and I hope you leave hospital soon. Yes the steroids mess up your sleep and can affect you mentally. Sorry the care doesn't sound great but the staff are likely to be trying their best in impossible circumstances so try not to get too frustrated (easy for me to say I know). Good luck.