How come I am not loosing any weight with all my efforts?

Ok so I am a beginer at running im a 21 year old girl and Im 124 pounds with a height of 5.5.
I have been running for the last month 30 miles a week. So about everyday exept sunday. I run on the treadmill at 7.1 for 5 miles. so about 40 minutes or so. My heart beat is like 180 to 184 the whole time im running. My weight hasnt change and my waist either. Im watching what im eating no junk food or anything. What is my problem ?

Weight is a poor way to judge the benefits of diet and exercise. Some experts recommend not paying attention to the scales at all. If your body is exchanging fat for muscle, your weight might remain the same but you're benefiting and should continue what you're doing. Muscle burns more calories than fat so keep it up.

Weight vs muscle and fat:
http://www.everydayhealth.com/weight/busting-the-muscle-weighs-more-than-fat-myth.aspx

I think You have to meet one of the good and expert coach who trained you very well and give you your solution as per your expectation.
Thanks