Why is my boyfriend suddenly acting like a jerk?

We've been together for almost 6 months, and for about 2 weeks he has been acting like a jerk. He brags to my mom about how much he drank, how drunk he was, etc., he won't invite me anywhere, he lies to me about little things, and is really rude whenever I talk to him. What is going on? Is he getting sick of me? I am getting sick of him.
Why is my boyfriend suddenly acting like a jerk?
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