You may find that your fridge isn't getting cold, but the freezer is just fine. If the inside fan is running, you should feel cold air blowing in through the diffuser in the top left corner of the fridge. If not, either you defroster is broken and ice has built up, or the diffuser is broken.
On ours, the diffuser door motor pushes on a small, fragile tab on the diffuser door. The tab snapped off. Rather than purchase a new $80 assembly, I fixed it with a toothpick and super glue. This fix may or may not last forever, (worked for about 3 years), but even if you want to replace the diffuser, it'll help you keep your cool until the replacement comes.