So earlier this week, i took my powershot SX60HS out for some shooting and everything seem fine just like usual. Next day morning, I decided to have a look at my results from the playback mode and i realised that about 300 or so photos i took 2 months ago have disappered while the new one are still here. I did some searching on the web and i can't seem to find the reason behide. This is driving me nut. So what does this mean? Does it imply that the SD card is currupted? and what can be done?
Yes, it does imply that the card has an issue. You need to get all the images off the card and re-format it - preferably in the camera. Or just get a new card.
You might try looking at the card in a computer to see if they turn up.
Card file recovery is probably not an option since you have used the card so much since they went missing.
Never use your in-camera card for long term storage. Make a backup as soon as you can.