Am I becoming an alcoholic?

Hello. I'm 23 year old male and I'm pretty worried right now because I'm afraid for my health. About three years ago I started to use alcohol. Not by my self, but along with my friends.
We just started to go out and every weekend we use to drink a lot before we went out. Of course, I didn’t think this could be anything serous but, now I don’t think so.
We are drinking like this almost three years now and weekend’s drinking become now drinking on daily basis. It’s very hard for me now to get drunk because I have to drink a big amount of alcohol. What does this mean? Am I becoming an alcoholic? How alcohol affects health?

I see why you are so worried and I can only say that it’s about time to start thinking about your health. Answer to your question is simple.
Alcohol is a problem for you if it causes problems in any part of your life- social life, love life, job and your health.
I'm glad you understood that alcoholism is a big problem and that you were on the right track to become alcoholic. You don't reach this stage overnight but after several years of alcohol abuse.
Alcohol can cause several effects on your body. Many people first think on liver cirrhosis but beside this it can cause stomach pain due to a bleeding ulcer or irritated stomach lining and even a depression.
Quitting is the only way to stop the problems alcohol is causing in your life. The solution maybe sounds easy to you but believe me- it can be very hard.