Hammer setting on all the time on my cordless drill?

Hi

I have a Macallister 18V cordless drill, Recently it has been used most days however the yesterday the hammer seems to be constantly stuck on, Even the simplest of tasks (screwing into wood) is taking longer and extra strength the get the job finished, the tork setting is the same as it has been since I used it and I have never used the hammer setting when ive used this drill in the past. Model: COD18VCHD