You start the course in September, so now would be a good time to do some exposure therapy and CBT. I had VERY severe social anxiety for A VERY LONG TIME sorry for all caps, but I can't stress how bad my anxiety was. These days it is manageable, and I even managed to get a job when before I could hardly leave my room let alone the house. Honestly facing your fears is the only way. I wish I could tell you of some magic cure, but the only way to fix and learn to cope with your anxiety is to face it and push yourself out of your comfort zone. I know it's hard, and uncomfortable, but it's the only way. Put yourself in uncomfortable situations (social anxiety wise), and use CBT to help you cope. If you haven't already, go and see your GP and explain your issues, also there are plenty of online resources for CBT and exposure therapy.
If you put in the work and start facing your fears, pushing your comfort zone, challenging your negative beliefs and replacing them with realistic thoughts, be consistent even when you fail, you will be more able to cope with your anxiety in September. It won't go away, it's anxiety, we all have it, but it will be better than it is now.
Good luck from a fellow social anxiety sufferer.