I have no problem maintaining a level technically in the tunnel. The problem is that that I start to panic when I get above head height. I am also able to fly in different wind speeds without problem.
In the tunnels I have been in, the wind is very constant up to 5-ish meters.
I think I need to do some VR therapy or CBT or something.
Maybe try to increase your height slowly overtime. For example, one one day spend a bit of time working at 6'. Then the next day spend a bit of time at 7' and so on and so on. Or you could try forcing yourself to spend a bit of time higher than you feel comfortable every time you fly. Say ok I am going to spend 30 seconds at 10' no matter what today. If you do that enough eventually it will become the norm and you'll probably lose your fear. Most fears in most sports universally come down to the same thing. People are afraid of the unknown.They like to be in situations they can control, or at least have enough experience that they can accurately predict the outcome. If you do something that is unfamiliar often enough, eventually it becomes familiar and then the fear goes away.
Great advice! Will try to set aside time for just getting used to going higher and higher slowly. Usually, all the focus is on doing new tricks/skills. Since I am scared of going high that is a skill in itself which most other flyers don't have to "learn".