Agreed. I would recommend trying a new sd card to see if the issue stops. If so, the original card is bad.
You'll have to perform tests on the card from a PC. The best tools are H2testw & FakeFlashTest.
Every time you purchase a new sdcard always verify the authenticity of it! Fakes will show a spoofed amount (ex. 4gb card sold as 256gb), and they're not as durable.