I use a SSD for my main drive. I do have an HDD, but it's just for backup files.
I'm not sure what I did, but the problem may be fixed, for now. I opened up the computer and double checked that everything was plugged in well, but I didn't notice anything wrong. However, the problem seems to be gone. I only tested for about 20 minutes though, so I think it's probably to soon to claim victory.