Worried a lot (major aniexty)!!

Agh I get this aniexty where it’s called realization I think and my high school graduation is soon we are going to be in a big field with a lot of people and I’m worried I’m going to panic and have everything not feel “real” I thought about just having them mail me the diploma but I don’t wanna let down my family .... it’s really hard for me to control that kinda aniexty and I know it will happen because those things trigger me :(( I wanna be normal