really worried teen

have health anxiety especially about brain tumours and ever since i have iv noticed these episodes. when im stressed especially the happens it just feels like one min im awake the next i just skipped time for a few secend i have no after symptoms or before but sometimes i feel a bit tried before and i close my eyes and just skipped time. it worry’s me as its a sign off brain tumour and just need some reassurance stress and anxiety cause do this . thanks