How do I stop having certain dreams?

Ok, so my girlfriend broke up with me about 2 months ago. We had been together for 2 years. The first 3 or 4 weeks after the break-up I still wanted her back. Then we ended up having a huge argument over what seems to have been a mis-communication. So we haven't spoken at all since. I thought after that situation that I didn't want her anymore, also because her behavior and personality seemed to have been different since the break-up. All of our friends have noticed it too. But since the initial break-up, I still dream about her, even after I thought I didn't want her anymore. The chances of her and I getting a second chance are a billion to one. So I would just love to quit dreaming about her. Because it just gives me mixed feelings when I wake up. The dreams are not every night, but usually once or twice a week.