Hi, Jennifer,
Thank you for asking a question here, and Welcome to this site. I am sure you will get many good answers.
Only your boyfriend can say for sure, but he has all the signs of being an Alcoholic. Within some time frame, and it's different for different people, alcohol changes attitudes... from Mr. Jeckyl to Dr. Hyde, or whichever way it should be.
Alcoholism eventually causes one to have very, very bad attitudes, going from a "happy drunk" to a very mean, argumentative, and sometimes violent person when drunk. I am 64 yrs old,. been there... done that!
Please believe me when I say that you cannot change him! Only he can change himself, and it will not happen unless some drastic, severe, event happens in his life. Some even kill others in car wrecks, 2nd degree murder, etc, and still remain in "denial"... meaning they don't see a problem.
There are two things you can do, and the choice is yours.
First, look in your local phone book for AA (Alcoholics Anonymous), and ask for the nearest Ala-Non meeting. The Ala-Non meetings are free, last 1 hour, and you will meet others who are experiencing the same thing you are. From their experiences, you will learn more than you ever dreamed in just 1 short hour.
Your other choice is to forget about him, and move on. If you stay with him, and try to help him, it will only get worse. It always gets worse, not better.
His drinking will become more and more, everyday, and his attitudes will get worse, not better.
If you wish to know more information, there are many sites online which can also help enlighten you, such as:
http://www.alcoholics-anonymous.org/?Media=PlayFlash
There are Alcoholis Forums all over the web.
I do wish you the very best, and also please realize that if you stay with this person, your own attitudes will change also.
You have taken the first step in admitting there are problems with your relationship. Congratulations on that.
The next step is up to you. Either attend an Ala-Non meeting to find out what you are up against, or make some other decision. I do wish you the very best, and you are not alone!