I really cant tolerate any pressure

Is anyone else like this? I feel really stupid for it but I feel like anytime Im under pressure I just freak. Its my last year of school, I was meant to be back Monday but we had a poorly planned trip and our flight was like last night. My mother kept reminding me Ive school tomorrow and kept getting calls from them and that combined with just being exhausted from a trip caused a huge meltdown and fight. I know Im in the wrong because I was taken on a trip and Ive caused my mother stress and betrayed her trust but I just cant. Im not sure how to overcome this because Im never going to be able to hold down a job if I crumble at any bit of pressure. And by crumble I mean meltdowns that legitimately make me a danger to myself and others.

Im sort of textbook spoilt since my mother goes through a lot of lengths to keep me happy and lets me go to concerts and all that but I just get really upset when I want help during a meltdown and my parents along with my therapist tell me Im being selfish. I want to go to school and get a job and I dont want to destroy my relationship with my parents again but I dont know how. Sometimes I feel like I give myself too many excuses but on the other hand the world might as well end during a meltdown.