It has been a week since my wisdom teeth extraction and the left side of my mouth still hurts. What should I do? I'm afraid of a dry socket.

Dry socket. You should go back to see the dentist who did the extractions. It may be a dry socket. They will be able to make the determination. There are treatments to help with the pain while it heals. If it is a dry socket it usually takes from 10-14 days to run its course.
Depends. Call the dentist who extracted the teeth, they need to see if the pain is considered to be normal for a difficult extraction or if you truly have a dry socket, it needs to be correctly treated. If necessary, they may determine antibiotics should be taken. See your dentist.
When?, relative. Whether or not this is normal, a dry socket, or a problem with healing such as an infection depends upon the timing, degree of pain and whether things are getting or worse. This can easily be determined by your dentist once he sees you and discusses the issue. We can´t determine that over the internet. Call your dentist and have him/her evaluate the area.