I am sorry you had this experience. I need to present fairly often and I practice my presentation 5-10 times. This really helps me. It takes away some of the thinking, I can practice hard words or tweak phrases to reduce blocking opportunities. I get teaching is more interactive and it isn't quite the same. If you wanted to get some practice in, I would be happy to have a call with you and have a mock lesson to help you build up some positive experiences. I am a native English speaker so I am not sure how it would work but the offer is there either way. One other thing, I find in-person is easier than video calls. Maybe try private, in-person tuition instead.