Thinking about quitting the Ph.D. because I feel depressed in this town? I have been living in this town for 16 months, but I am in this Ph.D. position only for 4 months. For the other 12 months, I had been working as an employee in the same research group.

I really like the research, the project, the prof., the colleagues and also the stipend. The only thing I hate about this place is the town where I am living. It is becoming more and more difficult to stay sane. It is only a few thousand "old" people and things close at 6:30 in the evening. I have been used to the life of a city (in and out of my home country). This small town is driving me crazy. I am trying to be strong, but I am not sure if I can keep it up for 4 years.
Don't commit to anything until you know your options. If you can find a more "suitable" position then you can decide at that time.

But evaluate all the aspects, including the support you get, and the support you might get. Not just financial support. 

One advantage of your current situation is that you aren't going to spend more time on the degree than needed and you aren't going to be distracted by nightlife and such.