Viewfinder shaking in my sigma 18-200 lens with Canon eos1100d

So, I dropped my camera yesterday wasn’t a big drop and it was in its bag but today when I tried to use it the viewfinder has got an almost constant shake on it and all the photos are out of focus.

The shake sometimes disappears for an instant when I auto focus but starts again pretty quick.

I’ve swapped the lens for the canons original lens and theres no shaking so I can only assume the problem is with the lens. I’m travelling in central America so won’t be able to take it to a sigma shop, and I’d like to avoid taking it to any old shop if I can.

Any ideas what might be up?