I had lost few of my data from my Android phone's memory card
Its most likely a one time issue. No, you don't need to run and buy a new SD card. There is a high chance that the issue was with your phone or a rogue app on it.
Also, always back up your data to prevent a major loss.
Its hard and many times costly to recover data from Flash drive unlike a hard drive. I would suggest you let go and if preferable format the SD card and forget about it.

Its a problem if this happens again anytime soon. Also check your apps to see if you don't have any rogue app or a pirated app.