Lately my violin had been sounding very shaky, like the string is about to fall out especially when I play G or D, a litte on A and the E string is largely unaffected. I know I haven't really described it very well but does anyone have any idea what could be causing this. I got a new G string about a month ago so it should have been fine.

have you checked your bow isnt too loose or tight as this can cause a problem similar to the one you describe, if it dosent improve ask your teacher or in a local music shop/repairman.

Check your bridge, since you said E string wasn't affected, it might be slanted or bent.

Go check with a music shop, best the shop you bought the violin from.

There are two things that always cause this for me, check the fine tuners and see if they are fitted firmly and aren't loose. Also check that any little cylinders of rubber (i think they're supposed to be used to stop the string digging into the bridge?) aren't loose as these are usually the main cause of any awful shaky sound

Yes I think it may be the tuners, as it sounds a litttle rattly