New fear of cantering!?

okay so I am leasing this horse, he has a tendency to rush off at a canter so I always get a bit nervous before I ask him. But I brought my friend to watch me ride today and let's say it was not pretty. She kept making kiss noises (as if to ask for a canter) when I was trotting, this freaked him out and he started cantering really fast. I managed to get him to stop and then I walked for a few minutes and asked again (on purpose this time) and he rushed off and ran strait for a jump (I can't jump they were just in the arena) and steered him away but I felt like a was going to fall so I grabbed the horn and I was saying walk but he didn't listen and he ran me into a wall. It was amazing I stayed on and it for me really shaken up. So I trotted like normal for the rest of the time. Then I tried cantering inside (he is more hyper outside and I feel more comfortable in a small arena) and he did it but he kept stopping I was really hesitant to ask again because of the fear on him rushing off again. So I decided to end the ride on a good note and just did sown trotting figure eights. How can I get over my fear in a safe way? And get him to stop rushing off? I have a lesson tuesday but I would like to work on cantering again tomorrow. Now this is really strange that I developed this fear because last week I was fearless, cantering around and everything was going great , this week has been down hill severly. I feel like I have lost all the confidence I have gained, and I am back to where I was 6 months ago. Please help! Tips? Thanks!