Pleasee help I'm gonna cry.

I'm really scared. I am just a high-schooler (15 year old) and yesterday I had this really bad feeling that I was not real. I got really scared and tried saying hello to my parents to make sure I'm here. Because that was really scary to me, today all I can think about is that thing. And now I just felt like it again. Now yet again I was frightened but I tried controlling myself from crying because I'm on a trip with my parents and I don't want anyone to know.

P.S. this didn't happen to me for the first time. I have it for awhile but it happened very less and they were always just a minute long and were less scary.

I'm really VERY scared right now so any tips, advice or consoling words would help a lot.

Also I wanna know: Am I crazy? Am I too young for this? Am I mentally ill? Will I ever be normal again? Will this stay with me forever? Should I tell my parents? Are they gonna thing I'm crazy? Should I ask my parents to take me to a therapist? When to go to a therapist?

I'm so sorry it's a lot of questions I know but I really need help ;) I cant even enjoy the trip