I know EXACTLY, how you feel. I am 18 years old, and I've never been a drinker however I was smoker for about 2 years and I to used to suffer from anxiety. During that time I maintained a 3.7-4 GPA and exercised everyday (Under 6 min mile). The first year smoked a couple times a month. The second year I smoked about once a week and for about 2-3 months I smoked almost everyday. I quit for 80 days and started smoking again about once a week, then twice a week, then the everyday drill. I remember nights when weed was my everything and at the same time it was nothing. Eventually, I realized I was just chasing the original high and that real and lasting happiness can only come when you are not under the influence of anything.
The only advice I can give you, and in all honesty if you take this advice for what its worth it will help TREMENDOUSLY with your anxiety.
***BE MINDFUL OF YOUR THOUGHTS***
Your thoughts become your actions. If you think it your body will listen!!!Keep a journal everynight and right down. "I am happy without weed" and "I am comfortable in my own skin". DO IT even if you are high lol. I have two notebooks filled cover to cover with. "Today was a good day and I did not smoke, Tommorow I will be happier".
Also, the EASIEST, FASTEST and MOST EFFECTIVE way to get rid of anxiety is to spend less time on screens such as your phone, computer, television. I do not watch, television and I've finally sold my smart phone and my anxiety has almost completley dissapeared. The relief is so deeply satisfying. ALSO, Remeber that all life is beautiful and your existence is a miracle. Spend some time with your thoughts!!!
To be honest, the only way I got over weed was through meditation, exercise and service. Personaly, I believe all that matters is that you live your life with the greater good of humanity in mind. Be a positive influence on this PLANET, and do not partake in the negativity, our society is to often caught up in.
Your mind is a marvelous thing, you'll be amazed at what it can do!!!
I truly hope you can find the inner strength we all possess to simply let go. Trust me, you won't regret it! Feel free to email me and I will be keeping you in my thoughts! Do your best to stay positive!!! :)