Effect of cortisone injection?

Hi everyone, I'm very new on this sight but very happy to be here! I'm a mummy to a little girl called Bellina. Well she's 3 years of age. Just last week i took her to the vet for a blood test which came back absolutely fine but she is suffering from allergies, most probably the grass outside. I live in Italy so the weather come spring time is full of bugs. Anyway, my vet gave her a cortisone  injection, this is not the first time but for some strange reason a week has gone by and I've noticed that she's not her usual self...its like she has no personality whats so ever! she eats like a pig which i know is a result to the cortisone but this sluggish behavior is wierd.She seems to be thinking a lot or just generally not here. If anyone has had this happen to them i would love to hear your stories. 
Thanks a lot
Emma

I'm bumping this up in case it got missed by anyone.  I, personally, have not heard of something like this happening.  Have you contacted your Vet and asked them about it?  I would definitely start there and see what they have to say.

Hopefully that weird side effect wears off soon

Hi, thank you for your reply. I haven't been on the sight for a while.

I took her again to the vet and he did an ecografia(ultrasound) to see her little kidneys and liver and all was fine. Then he tested her glucose level and all was normal. I was panicking because I'm a terrible addict to self diagnosing via internet!.....Not a good idea. i was more worried of cushing disease in cats due to over use of steroids. She is in good health and nothing strange came up. Today for the first time in a month she ran across the garden, which shows her energy level has gone up. I really want her to come back to the annoying, nagging me all the time, kitty!

The vet did say that this could be from the effect of the steroid, intact he was very sure. He's a good vet...i hope. So we will see but so far all good.

Your cats are absolutely beautiful!!

Emma