My first time flying today and I’m terrified

I’m going to Cancun tonight and it’s hard to feel excited because I feel SICK honestly, I get severe panic attacks on the train in my city so I’m anticipating myself freaking out!! Can anyone here tell me what happens if someone has a medical emergency? Like my panic attack attacks always make me think I’m having a heart attack even if I’m not. Do planes have wifi? I will be with my boyfriend, but he doesn’t experience panic attacks so I don’t think I will feel that comfort.. also is there Wi-Fi on the plane so I can watch some breathing exercises?